should you buy bare or assembled heads


Staff member
should you buy bare or assembled heads ?
well lets put out a few facts for you to decide,
the ADVANTAGE in buying bare heads is in that
you get to select each component to be used in the valve train,"THIS IS A HUGE ADVANTAGE", and THEN YOU select a shop you trust, that can assemble and carefully custom fit those components you selected, too get the ideal balance between cost, light weight and durability,and make sure you get quality components,
but keep in mind you'll rarely save any money going this route, because most assembled heads are sold with crappy import valves and crappy valve springs installed in those heads, to keep the price low,so it generally means that you'll save money buying an off the shelf head,compared to buying a bare head and then installing quality components, but Make sure you disassemble those heads or clean the individual components and clean them up, carefully with a brush and solvent then lube and re-install them, carefully verifying clearances.they will have dirt, manufacturing debris and casting flash. all through them. Cleaning flashing with a dremel or die grinder in the port throat area under the valves , or behind the valves and in the ports will help them flow more consistently and generally up the port flow numbers. Gasket matching the heads and intake port areas and blending both to match the larger cross sectional area and extend that blended area an inch or more into the port runners will help them flow better also.
THE question about buying bare heads and having a local shop you trust add the valve train components and do the machine work , VS buying ready to run, off-the-shelf cylinder heads, comes up frequently.
the manufacturers can buy in volume and purchase valve train components a good deal cheaper than you can, and they can have heads machined in large batch jobs that also reduce machine work costs, but they are also trying to be competitive so they rarely select the top quality components, thus there's always a trade-off and you,ll rarely see top quality machine work, and the better components used in off the shelf heads for sale....that does not indicate the off-the-shelf heads are junk, but the manufacturers must balance quality and price to remain competitive.
Youll almost always find that the larger and better known brand name suppliers like

have listed upgrades as options
yes quality varies and your going to be doing research or your not likely to get the best value per dollar or best potential performance.

related threads and sub linked info

ID suggest you select from heads from these sources
Jegs; 800/345-4545;

Summit Racing; 800/230-3030;

Scoggin-Dickey Parts Center; 800/456-0211;


TRICKFLOW ... 4294867081
1-330-630-1555 • 1-888-841-6556


Dart Machinery; 248/362-1188;

toll free: 877-892-8844
tel: 661-257-8124

Patriot Performance
Patriot Performance; 888/462-8276;


Toll Free: 877-776-4323
Local: 901-259-1134

EDELBROCK ... main.shtml
Edelbrock; 310/781-2222;

BMP (world products)
Tel: 631-737-0372
Fax: 631-737-0467




the old rule that you tend to get what you pay for and theres no free lunch is valid

keep in mind, doing several hours or days research, on the difference in component quality, helps avoid problem's!
you will potentially get a much better, and more durable head assembly combo of parts and a better fit on the components used on the heads and the clearances that are too be used in the assembly process.
with no parts on a pre assembled head being paid for then thrown away, its seldom cheaper, to buy bare heads and assemble them correctly with quality components because you tend to buy much better QUALITY parts and take a good deal more effort in checking the assembly and clearancing those components you select and install during the process.

the quality of the machine shop work , you have done and the care taken during its assembly,you have done, on your engine can easily make or break the engine's durability long term

youll generally find that selecting high quality valves in a slightly larger size, and matching hardened valve seats and that have longer stem length than stock has the advantage of allowing you far more flexibility in the valve spring installed height and load rates, and dealing with a machine shop that specializes in high performance cylinder head work with a 4-0r-5 angle valve job and having some port and bowl area clean-up done,costs noticeable more than use of stock replacement components,and a 3 angle valve job, with stock replacement valve springs, but the increased durability , extra rpms and noticeably better air flow makes a big improvement in power over the whole rpm range
shop carefully your machine shop will generally help you if your unsure of the parts required, youll need valves that match your heads but the valve seats, valve length and diam. can be upgraded at extra cost, and its frequently worth the extra cost if your racing vs driving the car as daily transportation


you might also want to keep in mind theres a great deal more to setting up a valve train than slapping some springs and retainers and keepers on the valves.
read thru the links and sub links as theres a great deal of useful info, that youll want to know.
btw just a bit more info, there are valve spring retainers, valve spring seats, shims, valve retainer keepers etc. that can be used that have different sizes or depths that allow you to change the installed height, or relation of the spring to the valve stem , it compressed height, or the valve springs location in relationship to the stems locking groove
keep in mind shims under the valve springs can be used to raise the spring or shorten the valves installed height, valve locks and retainers can be purchased with non-O.E.M dimensions to adjust the valves installed height or spring load rates
you use either or both depending on the application
a .050 PLUS valve lock moves the retainer .050 higher on the valve stem with no other changes, a plus .050 retainer would move the retainer .050 higher with stock valve locks or an additional .050 if matched to .050 plus locks
if you used a plus .o50 retainer with a set of minus .o50 valve locks the retainer would remain at the stock height on the valve stem







valsp4.jpg ... roductName ... toview=SKU
Valves, Exhaust, NK-844 Stainless Steel, 2.300 in. Diameter, .372 in. Stem, 5.433 in. Length, Set of 8
Valves, Exhaust, XH-432 Extreme Alloy, 1.900 in. Diameter, .3715 in. Stem, 5.354 in. Length, Set of 8
if you just assume that the machine shop must have cleaned the parts they worked on carefully...

Ive seen cylinder heads returned still coated with valve grinding compound in the ports, and blocks with easily a teaspoon worth of mill chips in the crank case area. ITS MANDATORY TO CAREFULLY CLEAN ALL NEW COMPONENTS BEFORE ENGINE ASSEMBLY!


Here is an excerpt from an AERA TB,,

Exhaust Valve Guide Caution On
1965-98 GM Big Block Engines

These engines' valve guides were not intended as a replacement item from GM.
The guides were located into the head castings after the head was cast and
the exhaust guide is "water cooled".
The water-cooled guide also has two different size press fit diameters. Adding additional confusion to the matter, they also switched the location of the larger diameter sometime in 1985.

To determine which outside diameter guide you have and which direction to
remove an exhaust valve guide, the following procedure is suggested:

Drive the guide no more than .250" (6.35 mm) toward the valve spring side of
the head and stop. Then, measure the newly exposed area of the guide
OD next to the spring pad.

If the measurement is .620" it is the first style guide. To remove this
style guide, continue driving it toward the valve spring side of the head.

If the measurement is .616" , it is the second style guide. To remove
this style guide, you must drive it the opposite direction toward the combustion
chamber side of the head.
read ALL THE WAY thru these longer threads, yeah I know 90% of you will ignore that advice and I also know doing so will eventually cost you more cash than you can now even imagine!


CHEVY 882 smogger heads


rhs heads

most guys tend to run the valve springs that came on the cylinder heads they purchased,
in my experience, few even check valve train clearances until they run into problems.
most problems are rather easily avoided if you understand the need for checking valve train clearances, and degree in the cam, and talk to the cam manufacturers tech department guys, about your particular application, rocker ration, intended rpm range, and take their advice.
many guys seem to think that the tech guys just want you to buy more expensive components, or swap valve springs to boost their profits,
this is very rarely true, they don't want you to have issues/problems, as you'll bad mouth the product endlessly if you have a catastrophic engine failure, and they know that an extra hundred dollars in premium parts and careful clearance and valve train geometry checks can avoid that, making you far more likely to recommend their products to other potential buyers.
,that's one reason I was forced to learn how to do a great many things myself and had to acquire
a number of skills and a good many expensive tools,
as I got very tired of paying good money for sloppy half assed machine work,
and a we will get to your project when we get the time, and dealing with machine shops that think...
we damn sure won't put the time and effort into precise machine work that it requires in the vast majority of cases.

what you save initially, in lower price ,on any engine components
will more than likely be made up in the cost of required additional machining and time & effort added in required balancing/clearance work
you tend to get what you pay for, quality machine work and precision measurement and careful inspection processes take time and that costs money.
there is ALWAYS a compromise, made between quality and price
I learned that long ago,
“Quality is like buying oats: like:. If you want nice, clean, fresh oats, you must pay a fair price.
However, if you can be satisfied with oats that have already been through the horse ...
that comes a little cheaper.”:facepalm:

The following recommendations are from Erson Cams.
If you have questions, you can reach their tech department at 800-641-7920.
most cam manufacturers do extensive testing with each engine design to verify the limits and limitations of each engines valve train design, so it generally helps to talk with the cam suppliers tech department engineers.
cam lobe acceleration / de-acceleration rates have a large effect on the required spring load rates, as do rocker ratios and cam lobe size and lifter diameters.

sellecting valve springs, and setting up the valve train

How do you determine the spring pressure needed to keep the valves under control for a given lift, duration, and max rpm. It might take you several hours to read thru all the links and sub links but its time very well spent as it could save your engine from destruction and save you thousands of...
Hydraulic Flat Tappet Camshaft: 110 lbs Seat pressure/250-280 lbs open pressure

Solid Flat Tappet Camshaft: 130 lbs Seat Pressure/300-325 lbs open pressure

Hydraulic Roller Camshaft: 130-140 lbs Seat Pressure/300- 355 lbs open pressure

Solid Roller Camshaft: (Minimum Safe Pressures DEPEND ON SEVERAL FACTORS)

Up to .600Ë valve lift: 200-235 lbs Seat Pressure/600 lbs open pressure

Over .600Ë valve lift: 250-280 lbs Seat pressure /100 lbs pressure for every .100Ë of valve lift

before you reach for your wallet, do some basic math and read a few dozen related links
USE THE CALCULATORS to match port size to intended rpm levels... but keep in mind valve lift and port flow limitations ... ch_engine/

off the shelf heads normally use far less expensive parts and have noticeably less care taken in the assembly process simply because they are assembled in large batches and the price rather than getting the most potential from those heads is a big factor.
you generally don,t get the best bee-hive springs , titanium retainers,light weight valves on off the shelf heads.
look the only advantage to buying BARE heads is that YOU get to select the valve-train components, and in many cases the assembled heads are far less expensive in the long run, and in most case the assembled head components are acceptable, keep in mind the vendor doesn,t want you having problems but hes still trying to maintain a decent profit, so youll get durable but not always the lightest or strongest components.
you may also keep in mind that if the heads you select flow impressive numbers or lets assume 260cfm at lets say .600 lift and you then select a cam with .520 lift and an intake thats flows only 210cfm , the heads can,t possibly function at near their full potential


325cc BBC AFR heads
#3250-1 $2001 bare
#2101-1 $2485 assembled

your NEVER going to match that price adding top quality parts to the bare heads, but that doesn,t mean its a bad idea, in every case


watch video

$449 per head= $900 PER SET bare

this looks better deal all the way around, and yes they can be used with standard or shaft rockers

assembled heads at

this looks like a good deal also, and yes they can be used with standard or shaft rockers

USE THE CALCULATORS to match port size to intended rpm levels... but keep in mind valve lift and port flow limitations[/color] ... ch_engine/
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keep in mind swapping heads gives you the option to increase or decrease the compression ratio
of the combo

"(assume on a stock 350 small block)

Speaking in generalities and assuming no other changes, what's the relation between cylinder head combustion chamber size and overall engine compression?

Does just changing heads from a stock 76cc head, to a head with a smaller chamber make that much overall difference on engine c/ratio? Such as a 64cc or 58cc chamber. How about changes on necessary octane requirement?

Just curious to see what can be expected. I've read plenty on what performance gains can be had and what would work best for 350 TPI, but curious to see the other factors may play out.


Ok lets look at it a bit, theres two types of compression ratio, static and dynamic, keep in mind its MOSTLY dynamic compression ratio, that effects your results.
youll gain about 3% in hp increasing the effective static compression ratio one full point, so swapping from a 9:1 to a 10:1 cpr boost torque about 3%
swapping from a 76cc head to a 58cc head is a 1.84:1 cpr change so you can reasonably expect a 1.84 x 3% or a 5.52% boost in torque from that change alone.
if your current engine made 330hp that would jump to about 5.52% higher if the tq curve remained consistant, so youll see about 350 hp.

one of the the main functions of compression is to pack the fuel/air mix into a tight area for both fast effective ignition and to provide a mechanical advantage for the piston & rod assembly to push against the crank throw,as that mass in the combustion chamber burns and rapidly expands.

lets look ast your question, given identical 350 displacement engines with flat top pistons and a comon .032 thick head gasket, a .023 deck and 5cc valve notches, heres what your going to see in STATIC COMPRESSION,as a result of combustion chamber changes


keep in mind you want to stay at about 8:1-8.5:1 in DYNAMIC compression

to run comon pump gas without getting into detonation
that depends on the fuel octane, cylinder head temp. and several other variables but generally 8.0-8.5:1 dynamic works out well if your going to run mid grade pump gas



heres some different calculators ... sure.shtml
average the results
anytime your not sure about something, or theres a defective link, ASK, don,t assume.
I try too keep current but theres always going to be people changing the linked info on different linked sights
either product pictured below works on head bolt or rocker stud threads, simply dip the threads and screw into place




check all valve train geometry and clearance on any engine you assemble or modify the valve train on.

read the threads

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buying bare heads always looks like a great deal, and it can be on occasion, but
Bare heads will have valve guides and seats installed,
but will require final sizing and a valve job to match the valve you will be using, that requires a good deal of machine work, assembly time, the cost of the parts like valve spring cups, shims,valve springs, keepers retainers, valve seals, push-rod guide plates, rocker studs etc.
and that can easily run into $500-$800 extra over the cost of the bare head castings alone,
and youll rarely get out of the cost of components and machine work on assembling bare heads on the lower end of that range if you use top quality components.
and while its true that in many cases the assembled heads are assembled with cheap components that don,t compare in quality to what you might have selected individually the assembled heads do generally function and cost a good deal less up front once you understand the true cost totals.
you tend to get what you pay for and quality components and precise machine work are rarely cheap in cost.
the advantage as stated is the potential use of far superior components, but theres also the potential of badly done machine work or non-compatible components ruining the heads.
most of the less expensive commercial cylinder heads, and some of the ones you might think should be higher quality due to the brand name or cost, do not come with a top quality set of valve train components like valve springs and valves, they must remain competitive in cost so most have less than top quality machine work and valve springs etc. nor do the less expensive heads generally have a good quality multi angle valve job.
but you do generally get heads that will work after a quick clean -up and inspection.
if your smart you take the time and effort to disassemble and clean and inspect new heads to remove and minor flaws and machining debris, and verify the clearances, valve spring load rates and installed valve spring heights, retainer to valve seal and other critical measurements.
you might also want to cc the ports and combustion chambers and clean up any casting flaws or leftover machining debris, and verify the valve spring seats/shims installed heights valve seat concentricity and seal is what you want and are correctly assembled
before you install the heads on your engine

yes you need to as stated, many times on this and other websites, check all your valve train clearances carefully, but in this case theres almost certainly no cause to be concerned here as the minor difference in spring load rates and installed heights is probably well within the intended valve train and cams design limitations, keep in mind the max cam lift is .520

The answer to selecting the proper valve length in relation to the cam lift, and valve spring load rates, depends on the engine valve train geometry and the cylinder head design,
it differs from intake to exhaust on most engines also.
I've usually found longer valves are required if the valve lift exceeds about .630, but theres no rock solid rule, you need to do some research and call your machine shop and the cylinder head manufacture. the load rate also plays a significant part in that decision, thinner valve spring seats, is not always an option, as higher load rates require thicker castings for structural rigidity.
valve lift alone withing reasonable limits, has little to do with the need for longer valves, but as the lift increases the difference between the spring installed height and its spring bind or coil stack obviously changes.
if your standard valve spring has lets say a 1.70 installed height and a 1.20 coil bind or stack height you would generally be looking at .500 difference, subtract the .060 minimum clearance,
added to prevent binding issues for coil bind, that only leaves you .440 useful valve clearance.
now you can machine the heads in the valve spring seat area only minimally as the valve spring seats are over the coolant passages and generally ,
the manufacturers will tell you you can only machine the valve seat so far from the O.E.M. original location,
and in many cylinder heads you can't machine deeper without reducing the heads functional strength or causing problems.
if you can,t machine down into the valve spring seat, your other option is a longer valve stem, or if you just need about .040-.050 maybe you get by with off-set valve locks, or retainers, and longer push rods and valve lash caps.
but most machine shops would prefer the longer valves and longer push-rods to maintain the proper valve train geometry.
valves are generally available . .100,..200, .300 longer lengths for popular engines and you can certainly use a micrometer to measure similar valves from a different engine, if the proper length is not easily available.
be aware that theres both different valve stem diameters, valve lock location, valve lock designs, different intake and exhaust valve steels that you can,t interchange.
one of the old performance tricks some guys used to use on a BBC, engines with turbos, was to replace the 1.88 exhaust valves with 2.00 intake valves from a 430 lincoln engines that were made from exhaust steel.




before as cast

those heads (keep in mind that price is for a single (1) cylinder head)


you might also want to keep in mind theres a great deal more to setting up a valve train than slapping some springs and retainers and keepers on the valves.
read thru the links and sub links as theres a great deal of useful info, that youll want to know.
btw just a bit more info, there are valve spring retainers, valve spring seats, shims, valve retainer keepers etc. that can be used that have different sizes or depths that allow you to change the installed height, or relation of the spring to the valve stem , it compressed height, or the valve springs location in relationship to the stems locking groove
keep in mind shims under the valve springs can be used to raise the spring or shorten the valves installed height, valve locks and retainers can be purchased with non-O.E.M dimensions to adjust the valves installed height or spring load rates
you use either or both depending on the application
a .050 PLUS valve lock moves the retainer .050 higher on the valve stem with no other changes, a plus .050 retainer would move the retainer .050 higher with stock valve locks or an additional .050 if matched to .050 plus locks
if you used a plus .o50 retainer with a set of minus .o50 valve locks the retainer would remain at the stock height on the valve stem








youll have to correctly measure the clearance on your heads with the valve springs and cam specs you selected too use to know if you have the correct valve spring installed height and clearances, failure to accurately check frequently results in very expensive repairs and to what new guys frequently blame on the cam when it was a installers ignorance that was the true cause.








valve springs must be installed at a specific semi compressed and listed installed height,
to provide the listed load rates and clearances,


the cam you select will generally come with a suggested listed valve spring load rate and installed height,
and the loads are listed)

you must maintain minimum coil bind and retainer to valve seal clearance and proper push-rod and rocker geometry
the distance between the lower edge of the valve spring retainer and the cylinder head is adjustable to achieve the desired valve spring height through the use of valve spring seat cups and shims placed under the valve spring which can be purchased to lock into a stock height, or plus or minus about .050, and valve locks that cam move the retainer (stock or aftermarket) an additional .050 either tighter or longer allowing the valve spring to expand taller, shims can be placed under the valve seat hardened cups that are almost always mandatory on aluminum head but may be optional on iron heads,(O.E.M. cast iron and lower valve spring load rates)













max lift is installed height minus .060 minus coil bind

related info you really need to read

push rod to short

push rod to long

push rod length correct
Proform Pushrod Length Checkers 66789 SBC 3/8" rocker studs

Proform Pushrod Length Checkers 66790 SBC 7/16" rocker studs

Proform Pushrod Length Checkers 66806 BBC 7/16" rocker studs
a few simple tools will tell you if clearances are ok



think it thru, but have a long discussion with your heads manufacturer and any head porting shop youll be dealing with,because in many cases he can assemble the heads to match your goals cheaper and easier than you can.
read carefully most times when you see big block aluminum heads listed for UNDER $900 they are either WITHOUT valves, springs,rocker studs and certainly priced PER CYLINDER HEAD NOT PER PAIR




EXAMPLE lets say you want 320cc BBC heads ... B320&dds=1
$1650 or so gets you two bare heads ... T803&dds=1
$2450 gets you a nice set of fully assembled heads set up for a roller cam

the $800 price difference looks like a great savings, but price out the parts and machine work and youll be hard pressed to match the assembled price

8 exhaust valves-$190
8 intake valves $190

16 quality valve springs $300-$650 a set

retainers $50-$140 a set

$120 for rocker studs

$60 for guide plates ... /?rtype=10

spring seats $47

$33 for valve seals

add about $300-$400 for your average cylinder head machine work, and a couple hundred dollar$ in discounts you won,t get that the cylinder head vendor probably gets due to mass volume discount pricing,and your saving $300 -$500 or more on the pre-assembled heads.
the problem that frequently results,
from taking advantage of the "SAVINGS" in selecting a pre-assembled cylinder head,
that is usually, being offered in the package deal price,
is that you generally have few if any choices in the QUALITY of the components being used in their assembly,
or the care and precision being taken during the clearance, fitting and accurate measurement and verification of the component clearances and valve train geometry.
or put a different way!
if you personally do the work or have a local machine shop you trust do the work using component you select your far more likely to spot and correct minor problems than some guy doing several dozen cylinder head assemblies per day, using components that were usually selected based on the lowest price part available in quantity that the company accountants and engineers could find to use, so the price of those assemblies could be price competitive.
remember there's ALWAYS a way to make a part cheaper or slap something together faster if quality and precise fit, is not the prime goal.
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above is a very typical machine shop invoice for reconditioning a set of used vortec heads, notice theres $982 plus in charges and theres a great deal more that could easily be required to recondition used heads, now add the rather typical purchase price of at least $200-$400 for a set of clean used vortec heads and you quickly find you could buy better heads for the cost involved
so be aware that just the cost of used or bare heads is not the total cost youll see.
Recommended Spark Plugs for Vortec Heads

  • AC Delco Rapid Fire Spark Plugs R44LTS
  • AC Delco Rapid Fire Spark Plugs MR43LTS
  • AC Delco RapidFire No 3 Sparkplug
  • ACCEL P526S U-Groove “SHORTY” Double Platinum (approximately 3/16″ shorter then R44LTS)
  • ACCEL 516
  • Autolite 26
  • Autolite 104
  • Champion RS12YC
  • Bosch HR10B
  • Bosch HR10BX
  • Bosch HR9DC

watch these videos ... ature=plcp ... re=related
I buy most of my replacement valve springs from these guys
(866) 799-9417
heres their ph#
Toll Free (866) 799-9417
I always just order the springs retainers valve locks and spring seats as a package deal (NOT CHEAP BUT EVERYTHING WORKS AND FITS) then you just need shims under the valve spring seats occasionally to get the correct installed height










good quality valve springs are fairly expensive, youll generally pay $250-$450 for decent valve springs and many guys start looking for far cheaper imported sets, that are of lower quality, at bargain prices, the problem is that you generally find a set, and comparing the price it makes it hard for some guys to remember YOU GENERALLY GET WHAT YOU PAY FOR AND THERE'S A DARN GOOD REASON THE IMPORTED PARTS ARE CHEAPER

theres several pictures in these threads that should help












read thru these threads and sub links, theres a great deal of useful info in those links and sub links, take the effort youll save yourself months of work and thousands of dollars if you understand ALL the info before you start buying parts

spending a few days or even weeks doing careful research well before you start writing checks or pulling out a credit card, can save you thousands of dollars and months of work, understanding the difference in component quality ,correct clearances and how and why each component is supposed to perform and the potential stress its under helps you make far more intellegent choices and tends to allow you to get an engine built that far exceeds the quality and performance of the average crate engine assembly
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I had the same machinist ridge in my Brodix IK200s that he talked about in the
second video. It's the ridge at the letter "A". I didn't remove as much material
as he suggested, but I did try to blend from the roof of the chamber into the
seat area thus removing the ridge.


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its not at all rare to pick up 10-15 hp or more with a simple port and bowl area clean up to smooth and blend those machined ridges , if you do more extensive clean-up work, that power gain can be doubled in some cases, obviously highly dependent on both the application, that the heads will be used with, and the heads that your starting with, to begin the transformation, from out of the box, or as received, to a fully tweaked head.
Generally the better aluminum aftermarket heads tend to be better than the mass produced O.E.M. cast iron heads.
but keep in mind the intake manifold you selected to use with the heads,and the headers used to scavenge the cylinders, must have an equal or greater flow potential, and the cam you select must match the intended rpm band and also allow the valves to open far enough and long enough to use that potential air flow.
If you have killer SBC heads that flow 330 cfm at .700 lift and 245cc ports designed to supply a 406 SBC spinning at 7000rpm and you use a cam with .520 lift and a 220 duration that limits power to under 5800rpm, an intake that flows only 280cfm you can be 100% sure the combo will not produce near to its potential power. with the correct parts
BlackoutSteve posted these pictures
What cylinder head?
With my 4.280" bore and AFR head, I am forced to use a 4.540" bore gasket because the chambers are wide and would otherwise allow the gasket to "hang" in the chamber.

For example..

A VIDEO DART VS 882 chevy heads TO WATCH ... v3ZkqZiMjI


obviously you will need to carefully port match some intakes to some head ports due to the wide variation in sizes and shapes
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hey grumpy, Im looking around locally and have found small block heads from both air flow research and trickflow that are in my budget limits,that look like a good deal on the 383 Im building, which would your select?

I run into so many guys that think you can just un-package new cylinder heads and slap them on any engine they build , and expect those heads to function flawlessly.
there is almost always at least an extra 15-hp-20-hp or more potentially easily accessed through minor port clean-up.
if your willing to disassemble the heads, port match the runners and clear up the casting flaws and smooth and contour the bowl area under the valves you could rather easily double or in some cases triple those potential power gains just by improving the port contours and removing casting flaws
your choice would depend on WHICH cylinder heads your looking at from each vendor and the CONDITION of each cylinder head, both company's you listed ,do make some very good quality heads, but Id agree in most cases the AFR will tend to be better, but NOT in all cases.
keep in mind the heads you need might not be either of those, do some extensive research, BRODIX, PROFILER,DART ,AFR, EDELBROCK,and TRICKFLOW all make at least some good heads, and its rather common for used heads to need repairs that are not obvious by a quick inspection, which can add a great deal to the cost by the time they are ready to run reliably.
keep in mind you might want to buy new bare heads and add your own valves, valve springs, retainers etc. because that way your sure it will match the clerances and spring load rates to match the cam you select, the wrong valve spring clearances or load rates could screw up a combo rather quickly.
I selected the trickflow heads on my 383 because at the time I purchased them the difference in cost was $450 but from research I found that the power levels after porting both heads was similar, but keep in mind that was 15 years ago and the AFR have been upgraded twice, the TRICK FLOW are now a totally different design.
one issue I see is the constant mental disconnect between the guys intended use when someone buys cylinder heads based on the posted flow numbers, and reality,
posted flow numbers and performance that results will vary significantly when you mis-match components especially when guys fail to realize the engine they are building has very few of the same components or dimensions matching the posted
“I see this problem constantly. If you read in the advertising that a certain cylinder head flows 300 cfm, on a SBC engine , very few people ask at what valve lift and what bore size and then, ask themselves if the engine they build will have much or anything in common. , if they used a 4.155 bore size to test the heads and your bore is less, like a 4.060 the resulting valve shrouding it can kill 30-50 hp because it leaves a ridge all the way around, the combustion chamber that was not there during the advertised flow test. People buy heads that were designed and tested on larger bore sizes or advertised in dyno test articles when an engine used a cam with much higher compression and a much more radical cam with a tighter LSA and more duration, and are stunned and disappointed to find they don,t get similar results using much less duration, lift and compression on a smaller displacement engine! The problem occurs because that valve size and cam lift and duration,must match the intended application, and that port is designed to flow X-amount in order to get the air speed in a certain range. So if your particular engines component list is nowhere close to the magazine articles configuration, you’ve not only killed the potential airflow, but you’ve killed the air speed and completely destroyed the advertised flow dynamics of the cylinder head you based the cylinder heads purchase on ,expecting the heads to flow as advertised.”
this works at both extremes, I see guys buy cylinder heads with much to small/restrictive ports who are convinced that a larger head will kill all the low rpm torque, only to find the heads strangle the upper rpm power,and guys that over cam an engine with too low of displacement and compression, and who fail to install effective headers and a low restriction exhaust behind the headers, who then erroneously blame the cylinder head port size for the lack of power that results.

I'm frequently amazed , that people in general don,t think to ask about options that are readily available when building or modifying custom performance engines, component parts don,t generally need to follow exact production engine specs and in fact its usually a dis-advantage to be limited to the use of some components physical dimensions.
most cylinder heads have rather limited casting thickness in the valve spring seat area thus if you need a lot more room to install a taller valve spring your limited on how deep and wide the valve spring seats can be cut, yet few guys realize that installing a longer valve also allows a taller installed height on the valve spring without cutting the heads seat area.









the reduced diameter of beehive valve springs usually eliminates the rocker too retainer clearance issue


valve guide cutters come in a wide variety of sizes as do valve springs ... 7AodHUQApw
vssq1.jpg ... 6981467968



AS a GENERAL rule any spring thats more than 1/16" out of square
(thats a distance of .062) in the diagram posted above, is something best use to fill a dumpster



Lunati Part # 73043

spring pressures are 108lbs seat / 339lbs open
steel spring seat cups, placed under the valve spring protect the aluminum heads , other wise the vibrating spring base eats into the head surface, shims under the steel spring seat allow you to get the correct installed compressed height


(in some cases shims will be needed to get the correct valve spring compressed height)
If more than one is used, the thickest shim goes on top next to the spring base!



valves up to .350 longer are easily available or found and purchased ... 7Aod7QcAxw ... alves.html ... ollerhtml/ ... kit-9.html


read related info ... gTech.aspx ... g_upgrade/ ... rings.aspx ... toview=sku ... -23-degree ... blockchevy


viewtopic.php?f=52&t=5537&p=16744&hilit=210cc#p16744 ... wer-how-to







A Sample Listing of Performance Valve Manufacturers

Comp Cams
3406 Democrat Rd.
Memphis, TN 38118
(800) 652-0406, ext. 13411

Crane Cams Inc.
530 Fentress Blvd.
Daytona Beach, FL 32114
(800) 652-0406, ext. 13412

Del West Engineering Inc.
28128 W. Livingston Ave.
Valencia, CA 91355
(800) 652-0406, ext. 13413

Electronic Chrome & Grinding
9128 Dice Rd.
Santa Fe Springs, CA 90670
(800) 652-0406, ext. 13414
Elgin Industries
1100 Jansen Farm Dr.
Elgin, IL 60123-2555
(800) 652-0406, ext. 13415

Ferrea Racing Components
2600 NW 55th Ct., No. 234
Ft. Lauderdale, FL 33309
(800) 652-0406, ext. 13416

KPMI (Kibblewhite Precision Machining)
580 Crespi Dr., Ste. I
Pacifica, CA 94044-3426
(800) 652-0406, ext. 13417

Manley Performance Products
1960 Swarthmore Ave.
Lakewood, NJ 08701
(800) 652-0406, ext. 13418
Milodon Inc.
2250 Agate Ct.
Simi Valley, CA 93065
(800) 652-0406, ext. 13419

Pioneer Inc.
5184 Pioneer Rd.
Meridian, MS 39301
(800) 652-0406, ext. 13420

Racing Engine Valves
4704 NE 11th Ave.
Ft. Lauderdale, FL 33334
(800) 652-0406, ext. 13421

RPM International Inc.
16313 Arthur St.
Cerritos, CA 90703
(800) 652-0406, ext. 13422
SI Valves
4477 Shopping Ln.
Simi Valley, CA 93063
(800) 652-0406, ext. 13423

Supertech Performance Inc.
3580 Charter Park Dr.
San Jose, CA 95136
(800) 652-0406, ext. 13424

Xceldyne Technologies
37 High Tech Blvd.
Thomasville, NC 27360
(800) 652-0406, ext. 13425

Zanzi Spa
Corso Vercelli 159
10015 Ivrea (TO), Italy
+39 0125251540
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seb.a said:
Hi everyone !

what do you think about these heads ?
Small Block Chevy Aluminum Cylinder Heads SBC350 220cc new bare angle/striaght

I guess AFR would be better but these are quite cheap and are in UK so the shipping cost will be a lot cheaper than if it comes from USA and I will no have to pay hundred of euros taxes. I am in France so I have to pay 35% taxes on the item + shipping price when it arrives from US.

Which one should I choose and Is that a good stuf ?

I want to built a 350 to 400+ HP L98.


before you start thinking that youll save a good deal of money on the purchase of those bare heads, youll need to be aware that the heads will require new valves, valve springs,valve spring retainers, rocker guide plates and rocker studs, valve spring retainer locks and spring seats and shims, and decent machine work, some port clean-up, valve seats cut and lapped. all of that can vary a great deal in quality and you will need to purchase the parts and have a local shop fit the components and clearance them.
those heads are generally low cost castings , or clones of similar brand name heads like EDELBROCK,BRODIX, OR AFR , but you will find that in many case the attention to the casting details like the alloy used the casting thickness and the precise machine work is NOT up to the same quality as the better known originals they are based on.
any time you buy new cylinder heads it makes a great deal of sense, to verify they are designed to match the block youll use, the piston dome shape, and to look for several independent reviews, from previous purchasers, that are NOT on the manufactures web site and to read through the fine print on specs on valve size,valve spring load rates , max valve lift, port cross sectional area, combustion chamber volume,suggested head gaskets, intake manifolds, and look for advice on matching cams headers etc.

It certainly won,t hurt to shop for vendors selling at a lower price, but be aware component quality in valves, retainers and machine work do vary wildly as does the care taken in the machine work being done, so you tend to get what you pay for!

yeah I know it will take you a couple hours
and your reluctant to do so,
but read thru ALL the links
it will save you a great deal of time and WASTED money later

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ive seen guys use those heads and ford ones like it, cheap chinese aluminum pieces... will definitely pick up power over stock heads, but be prepared for misaligned holes and ports, improper thread pitches, and all kinds of silly quality control problems. gonna run into the same argument you made earlier in the thread about getting a used set of vortechs and still paying 1400 bucks when you include all the machining charges

on topic grumpy i think its difficult to improve on most of the aftermarket heads we have available to us today. for the average guy i think a port match, some deburring of casting imperfections and a bowl polishing is about the extent of enhancement most heads need.

for an all out race car, a professional all out race porter with access to an engine dyno and a flow bench would be a better call than attempting to fiddle greatly with the as cast setups of most aftermarket aluminum heads today. i have no confusion about the fact that the guys at AFR and Trick Flow are smarter than me when it comes to cylinder head design. so to think i can somehow improve upon their work is arrogant of me, im just not that talented. however when using a stock head or somesort of factory casting, i think theres marked improvements with home porting if you do our homework and cut smartly. the manufacturer didnt have performance in mind when they made the castings for most of our cars. that i do believe even a dummy like me could improve on.
Grumpy has given us the Tools Phil.
Just takes time to read all.
He's training us to think like him.
a few useful links for related info

its generally a very good idea to keep all the cam, lifter,valve train and cylinder head components in matched sets, keep components in labeled matched sets, if you intend to reuse used parts in a rebuild. as each wears in, or laps in to its matched components a bit differently thus random assembly increases the chances of future parts



I can supply a few tips ,and bits of info for anyone willing to jump down the rabbit hole, when your looking to machine cylinder heads for different valve springs, keep in mind your machinist needs to be careful as enlarging or deepening the valve seat depth and diameter, if done too much weakens the heads and installing stronger valve spring load rates adds considerable stress, so its possible to run into problems rather easily , if machine work is too extensive, ID suggest calling the cylinder head manufacturer for info on that! along with having a discussion with your machine shop.

manufacturers can supply info , similar too but not limited too info ,like this
that DIFFERS with each head don,t blindly start machining heads for larger springs with higher load rates , ask and get the CORRECT answers first!

a video that shows sloppy or careless component prep work on a set of chevy performance heads
,keep in mind on any heads you get from any vendor or back from any machine shop you need to carefully inspect them for machine damage, machining chips and lack of cleaning.

valve spring compressors



the valve spring compressor design you use and the use of a large strong magnet can significantly reduce the tendency of those little S.O.B,s from poping off to parts unknown
$12 or so spent on a decent magnet placed next to the valve keepers during the removal process tends to significantly reduce the chances of lost valve keepers Springs/Store/13 ... ments/399/

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don,t ignore the basic machinist checks on any new component,you need too carefully clean components, on every any part you buy, because you can,t assume it was correctly machined or cleaned before it was packaged.
Jack just tried to install a new set of cylinder heads and in the process he cracked the cylinder head,I don,t know all the details yet,but he stated that he had not cleaned and tapped the threaded holes in the block, the threads in that block were coated with old hardened sealant and he failed to realize he had installed the incorrect length bolt in the head simply because all the head bolts, they were all hard to thread into the block and when he was tightening one bolt it some how cracked the head, hes hardly alone here, this type of stuff happens, but it happens far more often when the parts are not totally clean and threads chased and the proper sealants are not used. luckily for Jack its an aluminum head and the area can be welded and re=machined so the heads not a door stop,but its a good reminder to clean all the threads, check your using the correct fasteners, sealants and TORQUE SETTINGS ... xS87oWmVvI



WEARING A FULL FACE SHIELD and having a 5-6hp shop vacuum set up to suck the vast majority of the debris from the porting work out of the air is going to help prevent some accidents and getting crap in your eyes

before you install any cylinder head on any engine clean it carefully , verify there's zero crud in the internal passages, and verify the clearance that you can, and first clean both the block deck and cylinder head mating surfaces with a clean lint free cloth soaked in acetone,
don,t even think of using copper paint its not designed as a true sealant in a similar application, use the correct sealant

DO yourself a huge favor and carefully read the threads and sub links.. below
one other very frequent use for my shop vac is to collect metallic debris,
don,t forget to do the basic thread cleaning with a tap

and use a vacuum, and a lint free cotton clothe soaked in acetone

to clean parts and , magnets and tape to trap, and collect all the metallic debris, take the time too look thru the links above, it can save you a good deal of time and money and prevent problems





theres a whole bunch of math you can use to match your port, cross sectional area, valve sizes and cam lift and duration and LCA to the application. its would probably help to actually measure the port and bowl area, and keep in mind that the increase in the port size in the area near the intake manifold matching surface is a lot less important than many guys think


any of the performer or performer rpm heads will produce better power than the vortec heads on the 383 sbc is matched to that existing intake and nearly any reasonable cam selection, plus run cooler and weight less and be easier to repair or port if thats ever needed, that does not necessarily make them the only or best available option.

Look over the flow numbers very carefully.

Compare the flow at the lift matching your camshaft.

Some heads flow more at .500" compared to another head, but may flow less at .600"

DO NOT choose a head with larger ports than you need.

Horsepower is a function of RPM.
As such big horsepower numbers require high port flow.
If you are building torque for a street performance vehicle using overly large ports will result in reduced torque, poor acceleration.
This is because airflow through the port will be slower than desired.
The engine will come alive above 3500rpm, but if you are not revving it pass 6000 you will not realize the full potential of the ports.
Using a larger port works best with long duration and high lift camshaft and the use of a high speed torque converter.

Typically 180cc is considered as large as you would want for the average high performance street engine below 390cid.
A 400 to 420cid may work well with 200cc.
However aluminums heads such as the Air Flow Research street performance, Canfield and TrickFlow Twist Wedge heads all work very well with 195cc ports.
This is consider the result of more effective port design.
You will notice a larger port does not necessarily flow more.

While I do not attempt to favor one head manufacture of another,
AFR heads are consider by many to best the best performing overall.
They cost just a little more and until they get the new production shop up and running at full capacity, a set of Chevrolet heads must be order anywhere from 6 to 10 weeks in advance.

Flowing is a long list of heads you can compare. Look very carefully at the numbers and comments.
I will be more than glad to help you choice a pair of heads for your engine.

When trying to choose between an iron or aluminum head, consider the fact that aluminum dissipates head more quickly than iron. Retaining heat in the combustion chamber produces more power.
As a result the compress ratio needs to be high in an aluminum head to produce the same power output as an iron heads.
However, an aluminum head will allow you to raise the compression more than just the compensation requirement before pre-ignition or detonation (pinging) becomes a problem.
The result is additional horsepower and torque.

Maximum compression rations will vary due to attitude, octane rating of premium gasoline where you live, the camshaft duration and final drive ratio.
Building a motor with too high of a compression ratio will result in pinging which prevents further power increase and will over time pound out rod bearings and break ring lands. In extreme situation you may pound a hole through the top of the piston.
Running a compression ration .2 to .4 below the maximum recommended compression ratio for your application will only cost you 5 to 10 horsepower, but buy to a much longer running engine.

In studying head flow numbers keep in mind that they are only a guide. High flow numbers don't always equal more horsepower, and more horsepower doesn't always equal faster acceleration. It can be frustrating to choose the best head and the best camshaft for an application. So many choose, and all manufacturers cliam their product is the best. Dyno or track testing is the only real way to know for sure, but who can afford to do all that testing. I look to my experience the experiences of other engine builders, and magazine test articles to help, but that's all they are a help, until the engine is run, we all have to wait and see.

One last note. If you must pass a smog check your choices will be limited.
Some Edelbrock and TrickFlow heads are 50 State legal, carrying a CARB number.

Over the last few years coatings have become increasing popular. this is due to the fact that a coating can reflect heat back into the expanding gases during the power stroke.
This not only produces more power but will allow a higher compression ratio before detonation occurs.
Coating a piston cost about $20 to $25 each, but for the full effect to be realize you should also coat the combustion chamber and valves.
As a result of these added cost, this process is considered a premium for engine builds with a higher budget.

I can supply Mahle pistons for some applications (350s and 383s and some Ford engines) for about $550.

These pistons are very strong forging, come fully coated, are some of the lightest weight pistons available and have come unique narrow rings for less drag and more horsepower included in the purchase.
Ask for details.

The following is a reprint fro Chevy High Performance Magazine.




Intake Port cc & CFM @. 500" Lift

Chevrolet Production 441 Iron Head 155/201

The 882 head may have out-flowed this head but with the addition of larger 2.02-inch intake valves and some decent pocket port work these heads will out flow the 882’s. Keep in mind that with a small 155cc port volume these heads are great for making torque.


Chevrolet Production Iron 882 Head 151/205

This head had the smallest port size of all the heads we tested. A set of 2.02/1.60-inch valves can be swapped in but be aware that without blending in the short side radius, the results usually find lost airflow.

Chevrolet Production 462 Iron Head 156/212

This head was a small chamber head used on 327ci motors until the end of 1968. The flow can be improved a little with larger valves and port work but the additional cost of this is impractical in comparison to what you can by some other aftermarket casting for.

Chevrolet Production Vortec Iron Head 885 170/239

This head can be seen as a sleeper when compared to other GM production heads. It outflows the LT-1 aluminum Corvette head on the intake side, plus its mid lift numbers are very impressive. This head is perfect when iron heads are required. GM designed this head and put it on trucks as well as on the later Impala SS but with a different intake bolt pattern. As for production pieces these are one of our favorites.

Chevrolet Production L98 TPI Aluminum Head 163/196

This aluminum head was used on the Corvette TPI engines from the mid-Eighties until the LT-1 1992 motors were introduced. The 882-iron head out-flowed this head across the board. This piece is not our first choice for a performance head considering that the largest valve this head fits is a 2.00/1.55-inch combination and it has a 58cc chamber.


Chevrolet Production GM LT1 372 Aluminum Head 170/214

The LT-1 head was the next generation head developed for the small blocks after the L98 head. This head uses a reverse-cooling system, which means it can not be swapped onto older blocks. The 0.400-inch airflow numbers are great and with some port work, the addition of 2.00/1.55-inch valves can really wake these heads up.

Chevrolet Production LT4 Aluminum Head

The LT-4 is substantially different from the LT-1 casting, and the flow numbers explain why. The larger intake ports are definitely a contributing factor. For a production head these babies put up some pretty good flow numbers. Remember, like the LT-1 the LT-4 can only be used on a reverse cooling system block.
Chevrolet LS1 Aluminum Head 204/240

GM won’t be left out of category 3 with these heads. This head has great 0.400-inch lift numbers as well as a good E/I ratio. They also feature a more flat valve angle (15 degrees) in order to promote a better combustion chamber that’s shaped like a kidney to help direct combustion and reduce possible detonation. Remember that this head will not interchange with pre-‘93 small-block heads.


AirFlow Research 180 Aluminum Head 181/250
This head is the smallest of AFR’s line. It is intended for engines up to 350ci. The flow numbers are especially impressive on the exhaust side of this head, leading us to believe that a single pattern cam may be the best choice here. The E/I relationship is outstanding with and 84%, almost higher than any other head in this category.

AirFlow Research 190 Aluminum Head 191/262

This head has the best flow numbers of all the category 2 heads. Offering great flow throughout the entire lift range you can see this head doesn’t just put up one big number at maximum lift. If you’re looking for great flow from a mid-sized cylinder head this is definitely one of the top contenders.


AirFlow Research 210 Aluminum Head 215/271
Here is an extraordinary head. It has larger intake ports but with 240cfm at 0.400-inches of lift who cares? The E/I ratio is an incredible 75% making it hard to find anything wrong with these heads. This head may be a little much for a mouse motor but it is perfect for a big mouse somewhere in the 383 inch range up.
Brodix-8 Pro Aluminum 181/254

This head features larger 2.08/1.60-inch valves combined with a 181cc-intake port. With smaller intake port this head flows outstanding at 220cfm by 0.400-inches of lift and even better by 0.500-inches. Combined with a mid-sized port this, this is an outstanding choice for a strong 350ci or 383ci motor.


Brodix Track 1 Aluminum Head 216/246

The Track 1 head may be down on the numbers at 0.400-inch lift but it’s really competitive once it sees the 0.500-inch lift point. Add some short-side radius work and wow you’ve got a killer head. If you have a set of these heads there’s definite potential.


Brodix -11X 220 Aluminum Head 216/246

Brodix offers this large-port, 23-degree valve angle, small-block head as one of its largest ports in the stock valve-angle lineup. The low lift numbers are down a bit but in comparison to some of the others once the lift numbers increase you can see there is some serious airflow. These come available with minor or major port work depending on how you order them.


Brodix -1X Aluminum Head 223/278

The Brodix -1x heads feature a 40/60 valve spacing, meaning the centerline of each valve has been moved away from its standard location to accommodate a larger diameter valve and move both valves away from chamber walls for unshrouding. This means special offset shaft mounted rockers are needed and available from Brodix. It seems like a lot of R & D went into these bad boys and the numbers show it.


Canfield Aluminum Head 195/258

Canfield only sells this head with valves. One area to pay close attention to is the excellent low and mid-lift numbers. This head actually out-flows the Category 3 heads from 0.050- through 0.400-inches of lift.


Canfield 220 Aluminum Head 223/260

This race oriented small-block head requires the use of 0.150-inch offset intake rocker arm to accommodate the repositioned intake valve. The idea of spreading the valves apart is to increase valve diameter and improve flow. This head has 2.08/1.60-inch valves and probably works best on larger displacement mouse motors around 383-plus cubic inches.


Dart Iron Eagle S/S 165/210

Dart offers everything from street performance heads to full race heads. This Iron Eagle piece is the smallest head at 165cc port volume but its just what you need when building a stout street motor that sees occasional strip time. Compare its flow numbers to others and you can be the judge on this one.

Dart Iron Eagle 180 174/210

This head is also a big brother but to the 165cc Dart Iron Eagle head. The 180cc head reveals a respectable intake flow curve and an outstanding exhaust port. This head comes in many different combinations. You can order the head with straight or angle plugs, a 64cc or 72cc chamber, and in iron or aluminum. You will notice this head has better mid lift intake flow figures but the same full lift numbers as the 165cc heads, however the exhaust side flows better.


Dart Iron Eagle 220 220/258

The Dart Iron Eagle head here offers a budget alternative to the aluminum Conquest head. With similar flow numbers the only real big difference here is iron verse aluminum and cost. This head is offered in 200 or 220cc intake ports and with 2.02 or 2.05-inch intake valves.


Dart Conquest Iron 220 220/252

This head really likes to flow at lifts above 0.500-inches. The E/I ratio at 0.400-inch is a very good 72% and 68% at 0.500-inches. This head comes machined for both center-bolt and perimeter-style valve covers. The Conquest can be optioned with 200 or 220cc intake ports, valves up to 2.08/1.60, and in 64 or 72cc chamber sizes.

Dart Pro 1 Aluminum 215 221/253

This is perhaps one of the most versatile heads out there. While the low lift numbers don’t stand out, the higher lift numbers are on par with the rest of the heads on the market. This head is definitely best on high winding motors where consistent rpm is what wins a race.


Dart Iron Eagle 230 229/254

This is the largest of the Dart Iron Eagle series heads. They perform best on motors above 400ci-inches and with cam lifts above 0.500-inches lift. The E/I ratio is acceptable and the castings are made of good quality. These heads flow well and do not really require too much handwork to improve airflow.

Edelbrock Performer Aluminum 166/235

This head may first appear subtle in comparison to its flow numbers but don’t be fooled. The 166cc port makes for great torque and the E/I flow relationship is good. This head is perfect for a street/strip application. In our own personal experience we had a 355ci motor with 9:1 compression, a streetable Comp Cam (DEH 275), and an Edelbrock RPM manifold. With this combination we were able to achieve 420hp at 6,000rpm and 440 lb-ft of torque at 4,250 rpm.

Edelbrock Performer RPM Aluminum 170/237

The Edelbrock RPM head is the big brother to the Performer version. It still retains a small 170cc intake port volume providing great torque down low where it’s needed. The E/I percentage is no less than 70% with much higher numbers in the low-lift areas. This head is a step up from the Performer, flowing more air, which in return will make more power on the top end.

Edelbrock E-TEC 170 Vortec Aluminum 170/240
With the tremendous popularity of GM’s Vortec head, Edelbrock decided to design a head around the GM casting. This head features a 1.94/1.55-inch valve combination, and different port configuration allowing it to out perform the stock production Vortec head. However, the E-TEC heads are aluminum typically costing more than the production GM heads.

Edelbrock E-TEC Vortec 200/252

This head is the next step up from the smaller 170 E-TEC. It features larger valves and bigger intake ports. However, a Vortec style intake manifold must be matched with these heads. Up to 0.500-inches these heads don’t really out flow the stock Vortecs. On the other hand their exhaust ports are extremely efficient which help improve performance throughout the entire power curve. They are also aluminum, which can allow more compression with out detonation.


Edelbrock Victor Jr. Aluminum 219/255

This is an impressive head. It features a kidney shaped combustion chamber keeping the combustion moving, the flow is awesome from 0.400-inches all the way up to our tested 0.700-inches, and the E/I ratio is an amazing 81%. We see a head that flows some serious air and likes high lift roller cams.


Holley 300-570 Aluminum 172/232

This head from Holley comes with angled plugs and 69cc chambers, which are a big change from the stock 76cc smog chambers. The combustion chamber is typical of a late model design with a kidney shape that increases combustion turbulence lessening the possibility of detonation.


Holley SysteMAX Aluminum 186/242

This head is very similar to the -8 Brodix but it appears to flow a little better on the exhaust side. Again this head looks like it offers great torque potential with its well-proportioned 186cc-intake runner


Pro Action Iron 220 225/239

These heads can be purchased in many different intake port sizes. They are available with 180, 200, 220, and 235cc intake ports. They also feature a 64cc and 72cc chamber for your desired compression levels.


Pro Action Iron 235 Iron 245/242

These are the largest of the Pro Action lineup. The heads are advertised as 235cc intake ports but in our testing we found them to be 245cc’s. These heads are definitely for use on big mouse motors that like to see some rpm.


Trick Flow Specialties 195 195/250
These heads may not flow the biggest numbers but there should be little question regarding their performance that they can perform well. In CHP’s Nov. ’99 issue they were bolted on a mild 383ci motor and were able to pump up peak engine power by 15.5%. These heads offer some of the best power for the dollar on a mild small Chevy.


TFS Twisted Wedge 200/254

In an attempt to be different for the better, this TSF twisted Wedge head changed the valve angles from 23 degrees to 13 degrees. The really big difference here is what the exhaust side of this head is capable of. Only one other head (AFR 210) was even close on the exhaust side. The E/I was also a very respectable 77%. This head really can wake up your engine.


World Products Iron S/R Torquer 170/225

This head is very similar to the 882 head tested earlier. The valves are larger and the flow numbers at 0.400-inch lift are almost identical. At 0.500-inch lift the flow is up 15% over the 882 head. With prices to rebuild stock heads increasing all the time these heads would probably be one of your better investments.

even a new guy should easily get an additional 10-15 hp out of a minimal port and bowl area clean-up procedure after reading these threads & links, and 20 plus hp is not that hard to do, on many engines
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I do my own valvejobs.
One area you never know of exact on assembled heads is Valvestem to guide clearance .
Its real important on a high Rpm race engine.
Real stiff strong valvesprings used with most roller cams is hard on all types of valveguides.
They can be worn out in just 100 miles or less.
Only accurrate way is to measure with a small dial bore guage each valveguide.
And micrometer measure each valvestem.
Own the small bore dial bore guage set. Very expensive.
ID suggest you select from heads from these sources
Jegs; 800/345-4545;
I've found BRODIX I.K. heads are very good quality, and decent value per dollar,
for a high performance street/strip style engine

trickflow 230cc makes a good racing sbc head choice

profiler 210cc is a good compromise race and street strip head

related info
USE THE CALCULATORS to match port size to intended rpm levels... but keep in mind valve lift and port flow limitations[/color]



Summit Racing; 800/230-3030;

Scoggin-Dickey Parts Center; 800/456-0211;


TRICKFLOW ... 4294867081
1-330-630-1555 • 1-888-841-6556


Dart Machinery; 248/362-1188;

toll free: 877-892-8844
tel: 661-257-8124

Patriot Performance
Patriot Performance; 888/462-8276;


Toll Free: 877-776-4323
Local: 901-259-1134

EDELBROCK ... main.shtml
Edelbrock; 310/781-2222;

BMP (world products)
Tel: 631-737-0372
Fax: 631-737-0467




As the economy continues to come out of its slump, cylinder head manufacturers are seeing a growing demand for new cylinder heads that can deliver race-winning performance.

Whether the heads are upgraded aftermarket heads for traditional small block/big block Chevy and Ford applications, or hot heads for the latest generation of Chevy LS and Ford modular engines, people want the latest heads that make the most power.

Heads do make horsepower, but they don’t make it all by themselves. A set of killer aftermarket performance heads that are mismatched with a camshaft, valve train or induction system will never realize the engine’s full potential. It’s all about achieving optimum airflow and velocity within the rpm range where the engine is built to produce power.

That’s where many a racer has gone astray. They overbuild a street engine with race components that are designed to deliver high rpm power instead of building the engine to produce more low-end and mid-range torque. Even in all-out racing the engine with the biggest heads and biggest flow numbers doesn’t always win the race.

Is Bigger Really Better?

A lot of people are true believers in the “bigger is better” philosophy when it comes to selecting cylinder heads. Head manufacturers as well as those who port heads make a big deal out of promoting the huge cubic feet per minute (cfm) flow numbers they’re able to achieve using the wizardry of flow bench testing and CNC machining. Flow numbers are up, but the numbers can sometimes be misleading because of the way the numbers are measured.
Airflow depends on valve lift, valve area, air density and the test pressure. There are industry standard methods for calibrating flow benches and correcting airflow numbers to compensate for differences in air density. However, airflow values can vary somewhat from one flow bench to another depending on the methodology and equipment that are used to measure it. Most flow benches have a margin of error of around plus or minus one percent. On a cylinder head that flows 400 cfm, the margin of error could be plus or minus 4 cfm either way.

Because of this, comparing the airflow numbers claimed by one head manufacturer against those of another may not be the most accurate way of comparing performance. The only accurate way to compare one head against another is to test them on the same flow bench under the same conditions. Even then the airflow numbers won’t necessarily give you an accurate picture of which head will actually produce the most power on a given engine application.
It’s also important to note the valve lift at which advertised airflow numbers are calculated. How do their numbers compare to the actual amount of valve lift the cam and rocker arms in your engine will achieve? Big flow numbers at 1.00? of lift are meaningless if your cam and rockers only open the valves .850? or less. And on a street application, most engines won’t see much more than about .550? to .600? of lift.

Another point to keep in mind when comparing airflow numbers is that the valves reach maximum lift only once during the intake and exhaust strokes. Flow numbers at peak valve lift may be impressive, but what’s usually more important is how well the head flows at partial valve lift as the valves are opening and closing (which happens twice during every intake and exhaust stroke). Better flow characteristics at partial valve lift can have more of an effect on power and torque than big airflow numbers at peak lift.
Accurate cylinder head comparisons mean you should look at the entire flow curve from low lift to maximum lift. Once you’ve done that, you will have a much better picture of how the head will actually perform on the motor you are building.

Also, there’s more to airflow than big cfm numbers. Air velocity and swirl are also important. A port that’s sized properly for the engine displacement and rpm range will keep the air moving at higher velocity, resulting in more complete cylinder filling and more power. Air velocity affects both throttle response and low-end torque. That’s why heads with port runner volumes that are too large for a given engine application may not perform as well as a stock cylinder head.

Swirl helps route air into the cylinder more efficiently and promotes better air and fuel mixing for better combustion. Swirl and turbulence can also cause air and fuel separation in the combustion chamber, which is something that can be visualized by wet flow testing.

Valve angle (the angle of the valve stem with respect to the deck surface) also affects airflow, and here shallower is usually better. The configuration of the combustion chamber, valve shrouding and even the diameter of the cylinder bore are additional factors that also affect airflow and a head’s ability to make power.

The best way to compare cylinder heads is to bolt them on an engine and do a series of dyno test runs to see how they perform. The best head is not necessarily the one that makes the most peak horsepower in a narrow rpm range, but the one that delivers the best power and torque curves for the intended application. If you’re building a motor for a drag car, then peak high rpm power is what you want. If the engine is going into a circle track car, you want good throttle response and peak power in the mid to high rpm range. For a street application, a broad flat torque curve and lots of low and mid-range torque works best.

As Cast Or CNC?

There’s an ongoing debate as to whether or not ports in an “as cast” cylinder head flow as well as those in a CNC machined head. Many aftermarket performance cylinder heads that are sold with “as cast” ports are capable of delivering excellent performance out of the box with no additional modifications. The same goes for some stock heads (such as Chevy LS1 heads) that flow very well in their stock configuration. But there’s always room for improvement by either hand porting or CNC machining “as cast” heads to change the contours of their ports, bowls and combustion chambers for better flow. It depends on what you are trying to achieve.

Most CNC profiles are developed by grinding, testing and mapping various port configurations for a particular application. People who do this kind of work build up a digital library of port configurations that work well with various head castings, camshaft and engine combinations. This allows them to replicate a proven port configuration by entering the data into a CNC machine and removing the unwanted metal to modify the cylinder head.
Is the end result better than the best “as cast” head for a given engine application? It depends on the castings that are available and how well they flow compared to an optimized CNC port configuration for the same setup. With most high-end performance heads, a raw casting is CNC machined to specific dimensions for that application to deliver peak performance.


Bigger is better continues as the trend among Pro Stock drag racers. The 600 cubic inch “monster motors” of a few years ago seem almost puny next to the 850 and 900 cubic inch motors that are now commonplace on the drag strip. Sonny’s Racing now has a 1,000 cubic inch naturally aspirated motor that makes over 2,150 horsepower and 1,550 lbs. of torque. It’s hard to tell how far this trend will push engine displacements in the years ahead.
The bigger these motors get, the more air the cylinder heads have to flow to handle the added cubic inches. The availability of aftermarket engine blocks with wider bore spacing continues to expand, and with it the availability of larger cylinder heads from Brodix, Dart, Alan Johnson Performance Racing (AJPE) and others to fit these engines.

Another trend we’ve seen is that of reducing valve stem angles and raising the ports for increased airflow. This, in turn, often requires custom fabricated intake manifolds or special intake manifold castings to mate with the modified heads (ala Brodix, Dart, etc.). With these types of heads, installation is not a simple swap. Changing the head may also require changing the intake and exhaust manifolds, and possibly even the valve train configuration.
For small block Chevy applications, splayed valve symmetrical heads such as the Brodix BD Series heads are now available to replace siamese-style SBC heads. The symmetrical heads seal better and reduce the risk of head gasket failure in the hot spot area between adjacent exhaust valves on siamese style heads. The ports also provide a straighter shot at the valves than the ports on siamese heads.

What’s New

To find out what the latest cylinder head offerings are and what’s being done with some of these heads, we contacted various aftermarket head suppliers and engine builders for their input. Here’s what they said:


Tony Mamo of Air Flow Research said AFR has recently redesigned their entire line of small block Ford cylinder heads. “Our new Renegade line provides about a 20 cfm improvement over our previous Outlaw series of small block Ford cylinder heads. For example, our 185cc street head used to flow 270 cfm but now flows 300 cfm. That’s a gain of over 11 percent!”

Other new heads from AFR include a 15 degree small block Chevy CNC racing head that flows over 400 cfm with 285 to 305 cc port runners. Also new is a 13-1/2 degree SBC Chevy CNC racing head with taller intake ports that flows over 450 cfm. This head does require a custom fabricated intake manifold. Mamo said that eventually they will offer a matching cast manifold that will work with this head.

“We’re getting back into the high-end racing market with these heads and some other future projects we’re now working on,” said Mamo. “In the next 12 to 24 months, we will also have a square port Chevy LS6 head to add to our current line of cathedral port LS heads.”


A new line of “Head Hunter” series 23 degree SBC Chevy heads from Brodix features .400? raised oval intake ports with 225 or 234 cc intake runners. Jason Neugent of Brodix says the 225 heads flow over 335 cfm while the 234 heads deliver over 345 cfm. The heads do require offset rockers and use a steeper 52 degree angle on the intake valve seats and 55 degree angle on the exhaust seats with 2.150? diameter intake valves and 1.570? exhaust valves.
“The small block Chevy market has been good, and we’re seeing more demand for heads to fit blocks with 4.500? bore spacing that allow displacements of up to 500 cubic inches. We have some 13 degree siamese heads for these that flow over 380 cfm, and a symmetrical head that flows over 400 cfm.
“We’re also seeing more interest in big block Chevy heads for 600 cubic inch and larger motors,” said Neugent. For 496 to 600 cid engines, Brodix’s new BB-3 Xtra Series heads feature a two degree shallower intake valve angle for improved airflow. Available configurations include a choice of oval (332, 351 and 365 cc) or rectangular (366 and 380 cc) ports in “as cast” or fully CNC machined versions. Brodix says the CNC ported 338 cc heads flow over 440 cfm while the “as cast” heads are good for a 30 horsepower increase over standard BBC heads.

Butler Performance

Butler Performance specializes in building traditional big block Pontiac engines for both drag race and high-end street performance customers. Dave Butler says he modifies Edelbrock aluminum D-port cylinder heads to match the cam, displacement and application his customers want. The heads fit 1962 to 1979 389, 400, 421, 428 and 455 V8 engines with 4.060 inch or larger cylinder bores. The same heads can also be used on 350 engines if 1.66 exhaust valves are use and the top of the block bores are chamfered for valve clearance.

Dave says much of his business has been building Pontiac engines for drag racers, but lately he’s doing more high-end street, large displacement pump gas engines. “I’ll get customers who want me to build them a 600 to 750 horsepower street engine for their muscle car. To get there, I’ll CNC machine the Edelbrock heads with a port profile that best matches their requirements.” Dave said he develops his port profiles on his flow bench, and then hand ports or CNC machines the heads as required. “The Edelbrock D-port head flows 260 to 270 cfm out of the box. After reworking the head, we can make it flow 330 to 340 cfm, which is what it takes to reach these kind of horsepower numbers,” says Butler.
Butler says he’s also building some LS engines for late model Pontiacs using a variety of aftermarket cylinder heads from AFR, Edelbrock and RHS. “We haven’t done any custom head work on the LS engines yet as we’re still building engines and learning what works best. But eventually we will probably be reworking LS heads too.”


Bud Keating says “Our market continues to be small block and big block Chevy cast iron and aluminum heads, and small block Ford cast iron and aluminum heads. We don’t have any new heads for Chevy LS or Ford modular engines. Our main market is primarily cast iron performance heads for street, circle track and drag racing Chevy and Ford engines.”

Keating said Dart heads are available in “as cast” or CNC ported versions, and billet aluminum heads are available for drag racing. “The demand for cast iron heads is strong because some race sanctioning bodies don’t allow aluminum heads. Our cast iron heads provide an affordable performance improvement over stock cast iron heads, and are stronger than the stock castings.”


Eric Blakely of Edelbrock says his company now has more cylinder head applications for NHRA Stock/Super Stock small block Chevy LSX style LS-R canted valve heads, big block Chevy race heads, and Big Victor 12 degree, 14-degree and Big Victor III heads. For circle track, there are new SB2 & ROX heads, and Pro-Port Raw cylinder heads for both drag racing and circle track.

Edelbrock’s new “E-Street” line is an affordable entry-level cylinder head for street motors with cam lifts up to .500?. There is also an “E-CNC” line that is fully CNC ported for high performance street applications and entry-level race applications.

Some product improvements in various head designs include extra drain back holes, thicker walls for custom machining and/or porting, raised valve cover rails for added valve train clearance, relocating valves to fit the cylinder bores better and to reduce shrouding, and a special HIP casting process that reduces porosity and improves strength.

Goodwin Competition Racing Engines

Todd Goodwin’s performance engine shop is a full service facility with two engine dynos, a chassis dyno and CNC machining capabilities for doing raw castings and even custom pistons. Goodwin says most of his business is building engines for high end drag racing, truck pulls, off-road truck and also late model Mustangs, Camaros and other performance cars. “We work with all brands of aftermarket heads and can also do custom billet aluminum heads if that’s what a customer wants.”

When it comes to choosing or reworking cylinder heads, Goodwin says airflow numbers are only one piece of the puzzle. “You also have to look at port cross-sections, volumes, air velocity, valve sizes, the intake manifold, the design of the combustion chamber and even the tops of the pistons. It’s all about matching everything to get the right combination that delivers the kind of performance a customer wants. If we’re designing the ports and combustion chamber for a head, we also like to do the pistons because they are part of the combustion chamber, too.”

Patriot Performance

Chad Bowling says Patriot introduced their new Predator Head for Chevy LS engines about a year ago that features raised valve cover rails for extra rocker arm clearance. The head flows 303 cfm on the intakes at .600? lift, which is about 70 cfm better than the stock LS head. “This head will bolt up to the stock manifold but does require measuring and changing the pushrods.

“Our Freedom SBC 185 and 190 cc street performance heads are still our most popular products. The line includes cast and CNC ported versions with 195 to 225 cc intake runners for street and racing applications,” says Bowling.


The newest offerings from Pro-Filer Performance Products include a new 13 degree All American series head for small block Chevys in cast or CNC machined versions, a new splayed valve symmetrical port head with cast ports for small block Chevy engines, and a new Ford 460 canted valve cast aluminum head with oval Pro Stock style intake ports that flow over 520 cfm.
Michael Green of Pro-Filer says the shallower valve angle on the new 13 degree All American Chevy heads combined with the 300 cc fully CNC machined ports flows over 400 cfm. The heads also have a solid rocker bar for better valve train control.

RHS/COMP Performance

According to Kevin Feeney of RHS, the new Pro Elite LS7 rectangular port aluminum head is a clean sheet of paper design. “These heads are compatible with RHS LS race blocks and GM LSX blocks. The heads are CNC machined and have a shaft style rocker system that can mount standard GM LS7 rockers, which allows the valves to be adjusted. The heads have a 12-degree valve angle, with intake ports that have been raised .220?. But you can still bolt the heads up to a stock intake manifold. The exhaust ports are also raised .100? to improve flow. As a result of these changes, the new LS7 heads are good for a 35 horsepower improvement over the stock heads,” says Feeney.

Steve Schmidt Racing

At the recent Race EXPO show in St. Charles, IL, Steve Schmidt Racing unveiled a high unusual and unique two-piece hemi cylinder head for big block 18-bolt Chevy and Ford engines. The combustion chamber portion of the head is identical for both applications but the top half of the head can be swapped to make it fit a Chevy or Ford engine. The two halves are sealed together with copper o-rings.

“We’re currently running this head on a 648 cubic inch truck pull motor, but we also see a market for this head for Competition Eliminator, Top Sportsman and Top Eliminator drag race classes,” said Jeff Sams of Steve Schmidt Racing. “The intake ports can flow 640 cfm at 1.100? valve lift, which means this head is capable of making about 2.8 horsepower per cubic inch on a naturally aspirated engine. The head is machined from billet aluminum, and is available with or without water jackets. “The price: a mere $16,000 (yes, thousand!) per pair. Though expensive, the cost is still much less than high-end heads from some professional racing head suppliers.

Trick Flow

Trick Flow’s newest product is their Twisted Wedge Race 195 cylinder head for modular Ford engines. The heads are fully CNC machines, and are available as bare or fully assembled heads.
“This head has been optimized for engines with 3.700? bores, not stock bores,” says Mike Downs. “The head likes lots of cam lift and also works well with a turbocharger or blower on the motor. On an otherwise stock 322 cid engine, these heads have made 520 horsepower with the stock manifolds.

“We are also finishing up work on a rectangular port head for Chevy LS applications that should be production ready by the 2nd quarter of this year. The LS market is one of the hottest markets today, so this new head will be a good addition to our cathedral port LS heads that we have now.” says Downs.

World Products

World Products continues to market their stock cast iron cylinder heads under the World brand name, but their performance heads and aluminum heads are now being marketed under the Bill Mitchell Products (BMP) name.

“We don’t have anything that’s brand new,” says Bill Mitchell, “But we have a broad selection of heads for small block and big block Chevy, Chevy LS and small block Ford engines. Products include their Mowtown cast iron and aluminum SBC heads, Merlin oval and rectangular cast iron and aluminum BBC heads, Warhawk 15 degree LS1, LS2 & LS6 aluminum heads, Warhawk 12 degree LS7 heads, Windsor Jr. an Sr. FSB cast iron heads and Man O’War 10 and 18 degree SBF aluminum heads.

What’s Mitchell’s advice for choosing cylinder heads? “Ignore all the BS about flow numbers. Heads that have great flow numbers don’t always run that great. We have heads that can make 1,000 horsepower on a 565 cid big block motor, but do you really need that much power on the street? You really have to match the head to the application and build the engine around the head and camshaft combination.”
the crower steel roller rockers or similar rocker units will have a longer fatigue life, than aluminum rockers, and the bearing trunions are replaceable so they can be rebuilt after 60K-80K

,Fatigue limit, endurance limit, and fatigue strength are all expressions used to describe a property of materials: the amplitude (or range) of cyclic stress that can be applied to the material without causing fatigue failure.[1] Ferrous alloys and titanium alloys[2] have a distinct limit, an amplitude below which there appears to be no number of cycles that will cause failure. Other structural metals such as aluminium and copper, do not have a distinct limit and will eventually fail even from small stress amplitudes. In these cases, a number of cycles (usually 107) is chosen to represent the fatigue life of the material.


[color:red]READ THE LINKS[/color]


    • Siamesed Extra-Thick Cylinder Walls: Resists cracking and improves ring seal (minimum .300'' thick with 4.625'' bore).

    • Scalloped Outer Water Jacket Walls: Improves coolant flow around the cylinder barrels to equalize temperatures.

    • Four-Bolt Main Bearing Caps: In steel or ductile iron have splayed outer bolts for extra strength.

    • Crankshaft Tunnel: Has clearance for a 4.500'' stroke crank with steel rods without grinding.

    • True ''Priority Main'' Oil System: Lubricates the main bearings before the lifters.

    • Oil Filter Pad: Drilled and tapped for an external oil pump.

    • Rear Four-Bolt Cap: Uses standard oil pump and two-piece seal - no adapter required!

    • Lifter Valley Head Stud Bosses: Prevent blown head gaskets between head bolts.

    • External Block Machining: Reduces weight without sacrificing strength.

    • Simplified Install : Fuel pump boss, clutch linkage mounts and side & front motor mounts simplfy installation on any chassis.

    • Dual Oil Pan Bolt Patterns: Fits standard and notched oil pans.

    • Bellhousing Flange and Rear Main Bearing: Reinforced with ribs to resist cracks.

    • Note: Does not include cam bearings, freeze plugs, or dowels
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Ive suggested your average skilled mechanic or hot rod enthusiast,
spend time in doing research in, and then if they choose too,
cleaning up the bowl area under the valves , of casting flash,
and valve seat machining ridges,getting a multi angle valve job,
narrowing the valve guides port matching the heads/intake manifold,
and polishing and ccing the combustion chambers,
you should not be significantly altering or enlarging the ports or runners,
multi angle valve jobs should be left too the pros with the correct machinery,
and precise measuring equipment,
but a home shop can certainly lap valves and clean up the port and bowl area ,
and port match, and blend , polish and cc combustion chambers, etc.

reading links and sub-links generally helps
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if you know exactly what your looking at during the videos, its so darn important, and so obvious that anyone seriously into building engines,
needs to have the precision tools, gauges etc,
youll need to check and re-check the way the component parts fit and to carefully clean the heads you buy.
a great deal of engine proper,building, is related to carefully verifying that the carefully matched and selected, component parts are carefully hand fitted to the proper clearances and clearanced to the proper range in tolerances for the intended power and rpm range and in some cases adjusted or polished to provide the best possible function.
simple checks and a bit of blending, removing minor flaws, grinding, and checking cam make a huge difference in long term durability, and its certainly worth the time and effort in the fact well proven that doing so is frequently worth a bit of extra power.
now any minor tweak may not provide a noticeable boost in torque or power seen on the dyno, but the combination of dozens of minor checks and tweaks can provide a very noticeable power and durability increase!
Ive done stuff like taken a die grinder, or hand sanded, combustion chambers, and blended header flange openings, polished combustion chambers, cleaned up intake and exhaust ports
cced heads, and guys wonder why I bother, yet I find those same guys who take parts out of the packaging and slap the parts together are also the same buts watching my or the guys I've built engines for's tail lights... and they are certainly spending more time trying to tune out random and hard to locate and duplicate performance issues that seem to be phantom like coming and going at random.
over time youll eventually find that selecting a few higher quality components and carefully fitting them seems to provide a great deal more consistent and certainly, over time, more durable and repeatable power.
choices many guys never think about, like verifying the valve spring installed height, clearances and load rates, and selecting well matched valve train components rather than looking for bargains in individual components, tends to pay off in much better durability.
obviously dealing with a machine shop known to do quality and consistent high quality, 3 angle valve jobs is the first step in this process,
Yes ,Ive generally found you will need to disassemble and check run-out yourself and yeah,
that requires you purchase a few tools to do it accurately.

yes several vendors may use similar casting's, vendors like BRODIX have far more control as they cast and machine their own heads,or have heads specifically cast to their design specs,
the other vendors may be using very similar imported aluminum castings but the components, like valves, valve seats, springs spring seats, the installed height, valve keepers,
and retainers, being used in the heads assembly process and the care taken in doing the valve job MATERS
longer term durability maters more than low initial price
little stuff you might not think mater much can fail and cause major damage, the difference in quality between low price retainers , or valve spring seats, and yes the cost to the vendor for better quality units might only be $30-$40 on a set of heads, but a few 6500 rpm pulls will let you know the difference rather quickly
a 29 cent part failing can cost you a total engine failure, as can improperly machined and clearanced parts


valve seat angles and air flow

valve seat angles and the actual angles cut on the valve edges them selfs and how you have the area under the valve in the port bowl area cut and blended has a marked effect on your engines air flow. When you drop off heads to be machined, its MANDATORY you are very clear and specific about what...

selecting valve springs, and setting up the valve train

How do you determine the spring pressure needed to keep the valves under control for a given lift, duration, and max rpm. It might take you several hours to read thru all the links and sub links but its time very well spent as it could save your engine from destruction and save you thousands of...

ccing my heads

HELP I hope some can help me with a prob I am having. I started to cc my heads so i check all and found that they need to be ground. I have one at 64.3 so I started grinding one of them to be at 64.3 or there abouts. I ground a lot off and got a reading of 62 so I ground more off and came up...


you can generally verify valve seat seal with simply pouring alcohol into the intake or exhaust ports with what ever port your testing vertical and watching for solvent or alcohol seepage in the combustion chamber ,

alcohol will seep past a marginal valve seat seal contact far faster than water will due to its lack of surface tension, so its a better test fluid. hand lapping the valve seats tends to help.
hand lapping valve seats can be done reasonably easily and greatly increases valve seat seal.
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you DO REALIZE you can't just drop the valve train parts, kits they sell,
into or on, those bare cast heads
and have the result work RIGHT???:rolleyes:
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as with most technology, there's a rapid ongoing improvement in what parts are available,
what the components can accomplish, what other matched parts must be used, and as usual the cost is always going upwards.

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