sellecting valve springs, and setting up the valve train

read thru these links and their sub links



pictured above you see the last rocked badly out of alignment with the valve center line,
a good example why you need adjustable guide plates, this rocker if left too run off center like this, on the valve stem tip , will quickly destroy the valve guide and rocker


theres a good deal of useful info in this article ... index.html


Aluminum does have advantages, like light weight, and easy of machining compared to cast iron, example,cracks in valve seats on iron heads ",usually the result of overheating,"tend to result in coolant leaks that are not easily repaired, so you need a new cylinder head even if you had hundreds of dollars in port work done previously.
but on aluminum heads a bit of tig welding and machining for new valve seats repairs the heads rather easily





















heads might need to be milled to make then strait
it should be noted that if the rocker stud protrudes into the port it should be trimmed to the port roof as any threads sticking down into the runner disrupt flow and don,t supply extra support to the rocker stud,and stud threads should use loc-tite tread sealant.


The valveguides for the Vortec heads are the same as all other small-block cylinder heads, but the Vortec heads come equipped with large valveguide seals.

The valveguide seals keep oil from running down both the valve stem and valveguide, and entering the combustion chamber through the intake port at high-engine vacuum and the exhaust port when the engine is not running. This cuts down on engine smoke and exhaust emissions.

This is the valvespring retainer installed without the valvespring. The maximum amount of valve lift that the Vortec head will tolerate is the distance between the bottom of the retainer and the top of the valveguide seal.

BE aware you need to verify rocker adjustment lock nut to rocker slot clearance and yes it varies even with the same manufacturers different rocker designs


keep in mind the cam lobe ramp acceleration and valve spring load rates.
as any decent mechanic will tell you, you need to finish a race to win it and having a car that constantly breaks parts won,t be fun, and gets darn expensive very rapidly
if your valve train won,t remain stable and under control consistently and handle the stress at the cams intended max rpm, (plus a bit more) your almost sure to have low durability, lots of valve train wear and parts breakage!
lets say your comparing two similar cam,s with listed specs
ones got 215 duration with .450 lift,
the others got 215 duration with 510 lift
Id bet 90% of the guys reading that figure.....hey I get more lift with the second cam, thats obviously going to improve air flow & potential power, so thats the route to take....WRONG!!!

with flat tappet cams, if you exceed a certain lobe acceleration angle you tend to develop valve control and wear issues rather rapidly , mostly because the valve spring load rate required to maintain lifter to cam lobe contact at higher rpm ranges, potentially causes extremely high contact pressures between the two moving surfaces.

SPEND $10 and get a calculator ,in this hobby its a darn useful tool


Isky claims that the Comp XE cams violate the 47.5% rule. The 47.5% rule applies to flat tappet cams for SBCs with 1.5 rockers but the concept is still the same for other configurations where the designs are "on the edge" or "over the edge" for lobe intensity. For 1.5 ratio SBCs, the duration at .50 must exceed 47.5% of the total valve lift or your asking valve train problems. For example, take a Comp Cams Magnum 280H, with 230 duration and, 480 lift...230/.480 = 47.9% which exceeds 47.5% therefore would not pose a threat to components. We do not regularly hear about the older, safer HE and Magnum designs rounding off lobes anywhere near as often as the XE cam designs. Unfortunately, some of the Comp Cams XE dual pattern lobes break this 47.5% rule on the intake side so they are likely to be problematic. The design has "steeper" ramps that are too quick for durability and reliability according to other cam manufacturers. They will wipe lobes in a heart beat especially if you have not followed the proper break-in procedure. Other designs are more forgiving during break-in and less likely to fail.
ones got 215 duration with .450 lift,215/450=.47.7%
the others got 215 duration with 510 lift/215/500=43%

one factor I will mention is that each manufacturer tends to look at durability, ramp speeds and max lifter acceleration very differently, one reason I tend to prefer CRANE & CROWER is that they both company's in general realize the engine must finish the race to win and a busted valve train is a HUGE problem,they both realize, and design valve train components and cam lobes with DURABILITY and reliable valve control as top priority,s that are far more important than squeezing every possible potential HP from a cam lobe design at the expense of long term durability
The maximum amount of valve lift before the spring retainer hits the valve guide seal is 0.530 inches. It is generally accepted that 0.060 inches clearance needs to be maintained between the retainer and seal (0.530 - 0.060 = 0.470 maximum valve lift). The Vortec heads, as they come with the large valve guide seals, are only capable of accepting a camshaft with a maximum valve lift of 0.470 inches.

All small-block cylinder heads built before the '96 Vortec heads had two grooves on the valve stems.

The second groove accepts a quad ring. It sits just below the split lock retainers. The O-ring keeps the oil, which lubricates the rocker arm/valve stem tip, from running down the valve stem and into the valve guide.

Small Block Vortec Cylinder Heads Specifications - Heads Up!
The O-ring must be accompanied by a tin shield over the outside of the valve spring (left). The tin shield keeps excess oil from splashing on the valve stem and valve guide. The tin shield and O-ring must be used together to be effective. Installing the earlier double-groove valves, an O-ring, and a tin shield will allow the Vortec heads to use camshafts with 0.500 inches of valve lift, without machining the valve guides lower for clearance. View Related Article


  • ValveSpringClearance01.jpg
    33.4 KB · Views: 6
Last edited by a moderator:
Its me again, I am trying to set up my valve assembly the push rod checker I got is like the plastic one you show from summit. Its says to put it on the stud and that both ends should touch valve and pushrod at the same time. OK it touches the pushrod first but if I press the pushrod down about an 1/8 inch then its touching both. Wouldn,t that be the same measurement that I would get when I adjust the zero lash and turn the set screw 1/2 turn? Thanks for your daily help :!:
it sure sounds like your push rods a bit longer than ideal,usually the distance is more like 0.010-0.050", than 0.125" you describe,(with .010 - 0.0 being preferred) remember the lifter seat is supported by oil pressure, when the cars running and when parts get hot they expand, ID suggest the dye on the valve tip and looking for the rub marks as a further check
Proper push rod length is absolutely critical for peak performance—minimizing bent or broken valve stems, guide wear, and energy-wasting valve side-loading friction.
With the lifter located on the round base circle, position the Push Rod length Checker (make sure you have the Checker with the proper diameter hole) over the stud. Ideally the Checker should contact the top of the push rod and the valve tip evenly at the same moment, should the Checker contact the push rod first, measure the gap between the front of the checker and the valve tip, and purchase a shorter push rod of the correct length. Should the Checker contact the valve tip first, measure the gap between the back of the Checker and the top of the push rod, and purchase a longer push rod.
the process of finding the correct length push rods not that difficult, you install the correct push rod checker for your application,on a rocker stud, install the adjustable push rod, in place of the stock push rod after roughly adjusting the adjustable push rod to the stock length once the cam is rotated so the lifter, your using to verify the correct length is resting on the cams base circle, and then you extend or shorten the adjustable push rod so the plastic push rod checker just rests on both the tip of the valve stem and the push rod checker as in the picture above, this gets you very close to the correct length, you then use the machinists blue or a magic marker and the rockers you will be using to determine the exact correct length by centering if possible but finding the minimum sweep mark width so the wear mark on the valve tip as close to the valve stem center line as you can get it and the minimum side loading on the valve stem is found. centering the mark is less important than minimizing the rocker tip wipe mark width
Last edited by a moderator:
How to Select A Valve Spring

one factor I will mention is that each manufacturer tends to look at durability, ramp speeds and max lifter acceleration very differently, one reason I tend to prefer CRANE & CROWER is that they both company's in general realize the engine must finish the race to win and a busted valve train is a HUGE problem,they both realize, and design valve train components and cam lobes with DURABILITY and reliable valve control as top priority,s that are far more important than squeezing every possible potential HP from a cam lobe design at the expense of long term durability


notice the more aggressive cam lobe acceleration rate on the roller cam lobes

notice the stepped cam nose to fit retainer plate

With the many choices of aftermarket cylinder heads, most with "longer-than-stock" length valves, the recommendation of a specific spring for a specific cam is almost impossible. It is now necessary to select the spring that will best fit the cylinder head configuration. We offer the following as guide lines only:

1) "FLAT-TAPPET" cam/lifter applications (Street & Street/Strip) seat pressures

a. Small Block 105-125# Seat Pressure

b. Big Block 115-130# Seat Pressure (Note: Big Block applications need higher seat pressures due to their larger, heavier valves.)

2) "FLAT-TAPPET" Open pressures should not exceed 330# open pressure (sustained after spring break-in) for acceptable cam and lifter life.

a. Open pressures should be a minimum of 220# for applications up to 4000 RPM.

b. For good performance above 4000, open pressures should be at least 260# with stock weight valves. (Light weight valves require less spring open pressure.)

c. Spring open pressures over 280# can cause "pressed-in" studs to come loose; therefore, we recommend screw-in studs for open pressures above 280#.

3) HYDRAULIC ROLLER CAMS require higher spring seat pressures to control the heavier roller tappets and the more aggressive opening and closing rates available to roller cam profiles.

a. Small Block applications: 120-145# seat pressure

b. Big Block applications: 130-165# seat pressure

4) HYDRAULIC ROLLER CAMS use higher open pressures to control the high vertical opening inertia of the heavier roller followers.

a. Small Block applications need at least 260# for general driving applications up to 4000 RPM.

b. Moderate performance small block applications like 300-360# open.

c. Serious small block applications can tolerate 400-425#* open pressures and still expect
"reasonable" valve train life when top quality springs, pushrods, and lubricants are used.

d. Big Block applications need at least 280# for general driving applications up to 4000 RPM.

e. Moderate performance big block applications like 325-375# open pressure.

f. Serious big block performance applications can tolerate 450#* open pressure and still expect "reasonable" valve train life when top quality springs, pushrods, and lubricants are used.

*Note: Open pressures in excess of 360# require the use of roller tappet bodies made of billet steel. Crane hydraulic roller and solid roller tappets are made from 8620 bearing grade steel to withstand the stresses of high-performance use. Most stock hydraulic roller tappet bodies are made of cast iron and cannot tolerate high spring loads.

Applications are generally used for serious street/strip use and full competition. Most are not used in "daily-drivers" where day-to-day reliability is stressed. Instead, most of these cams are intended for "winning performance." These cams are designed with "very aggressive" opening and closing rates. High seat pressures are necessary to keep the valves from bouncing when they come back to the seat. In all cases, the valve action and spring pressures required mandate the use of high-strength, one-piece valves.

a. Seat Pressures are determined by valve/retainer weight, engine RPM and life expectancy of components before replacement is required. Milder roller cams require 165# on the seat as an absolute minimum. 180-200# is common for most modest performance applications. 220-250# is common for most serious sport categories and some circle track professional categories. Pro-stock and Blown Alcohol/Fuel drag applications use as much as 340-370# on the seat. (The racers sometimes change springs as often as every 1/4 mile run!)

b. Open Pressures need to be high enough to control the valve train as the lifter goes over the nose of the cam. Ideally, the minimum amount of open pressure to eliminate or minimize
valve train separation is desired. Any excess open pressure only contributes to pushrod flex,
which can aggravate valve train separation. For serious racing applications this can be deter-
mined only by experimentation and track testing. For general guidelines we offer the following:

i. Street/Strip performance with long cam/lifter life desirable, 350-450# open.
ii. Circle track and moderate bracket racing 450-600@ open.
iii. Serious drag racing and limited distance circle track racing 600# and more.

high spring loads don,t play well with cast core roller cams over long term use, and flat tappet cams are also subject to high wear with higher spring load rates, heres a very clear example of why you should only use Billet cam cores with roller cams having over about 320 lbs of spring pressure and why you MUST verify valve train geometry and clearances.

cast cam cores tend to wear and fail faster than hardened billet cores, under high stress



you might also want to remember that metal worn from the cam lobes did NOT vaporize, its more than likely that some of its embedded in the bearings,valve train and cylinder walls, because the oil filter won,t catch all of it, instantly before it circulates thru the engine
don,t forget as many guys do, that swapping to a higher ratio rocker changes the push-rod rocker geometry,and clearances, the heads and rockers used obviously effect the required clearance, but you'll usually want at least 60 thousands clearance on the push rods to slot measurements and you'll want to rotate the engine thru two complete revolutions while verifying that clearance, while watching the push-rod geometry as it changes as the rockers move thru their arcsand may require a different length push-rods.



ok after doing dozens of cylinder head valve spring upgrades I have some basic familiarity here. I usually buy valve springs from these guys Springs/Store/13


it helps if you know what your dealing with before making changes

youll want a spring with about a 130lb seat load and about a 330-350lb open load on most street hydraulic roller cams

the seat can be shimmed to get the installed height loads right and the valve keepers and valve spring retainers BOTH are available in plus .050 type designs so while it might require valve lash caps and longer push rods it is possible to get more retainer to valve seal clearance without major machine work.
I'm reasonably sure you failed to read thru the links


you get real close by using a push rod checker that matches your engine, rocker stud diam, etc.
(btw its upside down in this picture)
keep in mind all roller rockers do not have identical dimensions, crower offers .050 off set trunion designs ans the designs dimensions do differ slightly between manufacturers




the process of finding the correct length push rods not that difficult, you install the correct push rod checker for your application,on a rocker stud, install the adjustable push rod, in place of the stock push rod after roughly adjusting the adjustable push rod to the stock length once the cam is rotated so the lifter, your using to verify the correct length is resting on the cams base circle, and then you extend or shorten the adjustable push rod so the plastic push rod checker just rests on both the tip of the valve stem and the push rod checker as in the picture above, this gets you very close to the correct length, you then use the machinists blue or a magic marker and the rockers you will be using to determine the exact correct length by centering the wear mark on the valve tip as close to the valve stem center line as you can get it.




used with press in rocker studs



if your heads have push rod guide plates you are not supposed to use self aligning rockers as yes they will frequently bind the push rods up and keep them from spinning, if you have guide plates you want the NON-self aligning rockers
as I've pointed out dozens of times a day spent reading links will save you a week of work and a wheelbarrow full of wasted cash.


links may help




and you may need too use the correct adjustable guide plates when you find the push-rod alignment is in need of minor tweaking to get the clearance and geometry correct




using a louis tool, this tool is a GUIDE /tool for use with a high quality DRILL,its made of HARDENED STEEL that FORCES the DRILL BIT to drill thru the head to correctly lengthen the push-rod slot for increased clearance, they usually come WITH INSTRUCTIONS AND THE NECESSARY DRILL

Ive used either one of these two products, applied on clean dry threads by dipping the stud threads just prior to assembly on those threads, waiting a minute for the stuff to start to get tacky,then screwing them in for decades



Ive never had a leak or loose stud, never had any issues removing them if required ,with the proper socket and breaker bar later either,
BTW, remember to visually verify the stud length and cut them a bit shorter if required you don,t want the lower end protruding into the intake port and any threads doing that do NOTHING to increase the stud rigidity but they sure can reduce port flow rates if left sticking down into the air flow path
Last edited by a moderator:
lash caps, can be used to lengthen the valve slightly and protect the tip of the valve from excessive wear
It is some what likely that you can run the same length push-rod with the lash caps installed as you can run without them, but you obviously need to verify clearances and valve train geometry. The caps work great for guys who have high spring pressures ,they can give you some extra clearance from underneath the rocker arm to the valve spring retainer.
you might find that lash caps IMPROVE the geometry or you might find they throw it so far out new push rods are required, you need to verify not guess,THERE'S MORE THAN THREE TYPES. AND THE MOST COMMON JUST SNAP OVER THE VALVE TIP WITH A SLIGHT FRICTION FIT, the tip of the rocker prevents them from riding up on the valve stem, and coming loose
most sit on the tip like this picture

you are aware you need the lash caps to be the same diameter as the valve stem diameter??

valve springs are not square, they need to sit on a cup shim and use an upper retainer with keepers


once installed the valve spring max length is the installed height,
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!







max lift is installed height minus .060 minus coil bind


THEY COME IN different heights and diameters ... ash%20caps ... signs.aspx


THERE ARE COMBO LASH CAPS/KEEPERS, and locking lash caps

NME603122-16.gif ... 603751-16/



rocker body rubbing retainer BEFORE lash cap installed

rocker body clearance preventing its rubbing retainer AFTER lash cap installed
the advice earlier in the thread on checking push rod length should be re-read if in doubt


Because today's racing engines run at higher and higher rpm levels and the cam profiles are extremely harsh, the tip of the valve stem is subjected to a tremendous amount of pounding. These engines always run just on the brink of valve float-one of the most severe conditions that can exist. The best solution to this problem is the use of quality Lash Caps. These lash caps are precision machined and ground perfectly flat to maintain accuracy of valve train adjustment.They fit the valve stems well and can be removed with relative ease because of a tiny hole to relieve the suction created when removing the lash cap. The Chrysler "Hemi" engine has benefitted greatly from this design. A special version is available to accommodate the very short tip on these valves. For the ultimate in strength and reliability, you will not find a better part than the COMP Cams® Lash Cap. A must for titanium valves. ... 5/10002/-1 ... Id=1354633

obviously valve float and improper lash clearance can cause problems but in some cases, lash caps can reduce wear


in most cases when you see valve tip damage like this its the result of valve float or a weak valve spring or improperly adjusted valves alowing the rocker to bounce on the valve tip., in many cases youll need to swap to a higher spring load rate and new springs to prevent or reduce this damage

any time you find an inconsistency in the valve train components, dimensionally.
it generally indicates either wear or something that's just not right in the valve train.
Id suspect that the valve spring thats not sitting square is loosing its tension, so I'd have all the valve springs tested or replaced.
I know Ive always wanted to buy a decent valve spring test tool, as its a P.I.T.A. to take the springs you want tested to a local machine shop and pay to have the springs load rates checked and trust the guy whose doing the testing both gets it done correctly and bothers to separate the springs into different boxes . labeled with the load rates,if he finds some that do not show the correct load rates,thus in many cases guys just replace all the suspected springs after finding a couple they don,t think are correct.

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










I watched that video, and my first thought was......
hey I'm a tool junky, so what will this new tool do for me?
great, she has a rocker and she is depressing a valve spring and it reads 100 psi?
NOW what?

what does that tell her?
how far was the valve spring depressed too read 100 psi? if the valve retainer moved with that tool on the rocker at 100 psi, then thats a ROUGH guide to finding valve seat pressure
what she has there is a tool that might easily be used to locate a cracked or broken valve spring,
but not much else in the way of useful data, could be found with it, so what good is it? you could most likely do that the old way with a quick push down on each valve spring retainer with an educated/ experienced thumb!
it sure looks like these gals were selected because they look good in a video, and they probably had a 3 minute long ..Q-card based education on what to say and do, for the VIDEO.....if it was my choice and looking at the tools vs what they do for me I'm rather inclined to spend $515 and get something REALLY USEFUL

$220 for this

$268 for this

$515 for this

PROFORM's new billet aluminum 1000 lb digital bench top spring tester is the most accurate way to check spring pressure. Check springs up to 1.5" in diameter and 3 7/8" in height. Digital display reads in 1 lb (0.5 kg) increments, and has a back lighting feature. Peak hold and automatic shutoff are other included features. Search part number 66776 at for more information.

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
Last edited by a moderator:
High Performance Rocker Arms, Valve Springs, Retainers and Locks

brodix ph# 1-479-394-1075 (ALWAYS VERIFY PART NUMBERS SEVERAL,
the brodix rock stud girdle is part # BR-6435 and LIST price is about $230 you can get it for less if you shop carefully
BE AWARE that the I.K. 200 heads were shipped with BOTH 3/8" and 7/16" rocker studs ,
and the poly locks for the 7/16" rocker studs ONLY fit that rocker stud girdle
obviously you need to verify what your heads have before you order the matching rocker stud girdle
Verifying your engines clearances, and rocker geometry, and use of A rocker stud girdle and high quality roller rockers go a long way towards maintaining valve train durability
By Larry Carley

Upper valvetrain components have more of an effect on power and reliability than you might realize. Most engine builders know that changing the rocker arm ratio increases valve lift for more power. But did you know that changing the rocker arm pivot point can also reduce friction and the rate at which the valves open and close?

On a small block Chevy, altering the rocker arm geometry without changing the rocker arm lift ratio can add 15 to 20 horsepower at the rear wheels.

The stock lift ratio for a small block (SB) Chevy V8 rocker arm is 1.5:1, and for a big block (BB) Chevy V8, the ratio is 1.7:1. Bolt-on aftermarket high lift rocker arms with higher ratios are often used to get more net lift out of an existing cam profile. The most common high lift ratio upgrade for a SB Chevy engine is 1.6:1 rocker arms, and 1.8:1 rockers for BB Chevys. But some performance rockers now offer ratios as high as 2.0:1 or even higher!

Increasing the lift ratio adds horsepower with little or no loss in low rpm torque, idle quality or vacuum. By opening and closing the valves at a faster rate, the engine flows more air for the same number of degrees of valve duration. High lift rocker arms also reduce the amount of lifter travel needed to open the valves, which reduces friction and the inertia of the lifters and pushrods that must be overcome by the valve springs to close the valves. On the other hand, increasing the rocker ratio also increases the effort required to open the valves because of the leverage effect. The higher the rocker arm ratio, the greater the force the camshaft, lifters and pushrods have to exert to push the valves open. But when the valves close, the increased leverage of the rocker arms works the other way making it easier for the springs to shut the valves and push the rocker arms, pushrods and lifters back to their rest positions.

On SB Chevy engines, the stock stud-mounted rocker arms are supposed to be self-centering and self-aligning. The ball pivot inside the stamped steel rocker arm allows the tip of the rocker arm to follow the top of the valve as the valve is pushed open. This creates some back and forth scrubbing friction between the tip of the rocker arm and the top of the valve. And the higher the valve lift and the stiffer the springs, the greater the friction. Over time, this can cause side wear in the valve guides, tip wear on the end of the valve stems, and worn rocker arms.

Aftermarket performance rocker arms, whether they are stamped steel, stainless steel, or diecast, extruded or machined aluminum, usually have a roller tip to reduce friction between the rocker arm and valve. The roller, in theory, rolls back and forth on the top of the valve stem to reduce friction, wear and side forces exerted against the valve. Most stud-mounted aluminum rocker arms also have a needle bearing fulcrum to further reduce friction at the pivot point, and a hardened steel insert in the short end of the arm to accommodate the pushrod. Power gains of 15 to 30 horsepower are often claimed for aftermarket rocker arms even with stock ratios because of reduced friction. Aftermarket performance rocker arms are also stronger than stock stamped steel rocker arms, and provide improved reliability and longevity. But stud-mounted rockers have certain limitations.

One is that they often require pushrod guide plates to help keep everything in proper alignment, especially at high rpms and spring loads. Another limitation is that they can't handle valvetrain misalignment very well. If the rocker arm twists, it may bend the pushrod and/or allow the tip of the rocker arm to walk off the side the valve tip. If that happens, the rocker may push down on the retainer instead of the valve, causing the locks to pop out and the valve to disappear down the guide, destroying the engine.

The hot setup today is shaft-mounted rocker arms. Shaft mounted rockers would seem to be a throwback to the days before the first stud-mounted stamped steel rocker arms appeared on small block Chevy V8s in 1955. One of the features that made the SB Chevy such a performer was its lightweight, high revving valvetrain. But keep in mind, that was a time when maximum engine speeds were in the 6,500 to 7,000 rpm range, not 8,500 to 9,000 rpm or higher, and most engines were running single springs, not double or even triple springs.

Shaft mounted rockers have a number of advantages. One is better alignment. The shaft is rigid so the rockers are held in perfect alignment. This eliminates the need for separate pushrod guide plates while also limiting valve train deflection. At high rpm, pushrods and rocker arm studs can flex quite a bit, and the more they deflect the more it hurts valve lift, duration and valve control. This costs horsepower and can be seen on a dyno. So the more rigid the valvetrain, the less the valve flutter at high rpm. Shaft mounted rocker arms also provide extra strength and support, eliminating the need for a separate stud girdle. Aluminum stud girdles are often necessary to reinforce the valvetrain when a high lift cam (or rockers) and stiff springs are used. The girdle clamps around the studs and ties them together to reduce stud flex and the risk of breakage. But the girdle also makes it harder to adjust the valves. Shaft mounted rocker arms don't have that issue because the adjusters are on the arms, not the studs, and are easily accessible.

Mounting the rocker arms on a rigid shaft also eliminates the "jack hammer" effect that occurs with stud-mounted rockers. Every time the valve opens and closes, the change in valve lash that occurs with a solid lifter cam causes a stud-mounted rocker arm to slide up and down on its stud. This hammering effect can pull a pressed-in stud out of the cylinder head, and may cause fatigue failure in a screw-in stud or the rocker arm.

Another advantage of shaft-mounted rockers is better geometry. By lowering the pivot point of the rockers slightly with respect to the valves and pushrods, the arc that the tip of the arm follows is moved further down the curve. This reduces the back and forth scrubbing on the top of the valve, which reduces friction even more. One supplier of shaft-mounted rockers says this change alone reduces the torque it takes to turn a SB Chevy over by 80 ft. lbs, and is good for 15 to 20 horsepower.

Lubrication can also be an advantage with shaft-mounted rockers. Some have internal oil passages that route pressurized oil directly to the rocker arms and/or valve springs instead of relying on splash lubrication from oil squirting up through the pushrods. Shaft mounted rockers are available from a number of aftermarket suppliers, and fit not only stock SB Chevy and Ford heads but also most of the popular aftermarket heads made by Brodix, World, Edelbrock and others. The shaft-mounted rockers typically sell in the $700 to $900 range and are an excellent upgrade for any performance engine.

Another supplier of aftermarket rocker arms has taken a similar approach by redesigning some of their stud-mounted rocker arms for the LS1 Chevy. The rocker arms require milling the stud pads on the cylinder heads .170" to accommodate the lowered rockers, but the net result is better geometry, less side wear on the valves and faster initial opening that produces more horsepower.

What you may not know is that the actual ratio at which a rocker arm opens a valve is not constant, but varies as the valve opens and closes depending on the arc the arm travels and the position of the rocker pivot point with respect to the top of the valve and the pushrod. The stock LS1 rockers are mounted rather high and initially open the valve at a rate equivalent to about 1.54 to 1 before eventually reaching 1.7:1. The quick lifting aftermarket rocker arms, by comparison, lift the valve off the seat at a ratio that is closer to 1.8 to 1 and then goes to 1.7 to 1 at .200" valve lift. This has the same effect as increasing valve duration about six degrees, and produces 15 to 18 more horsepower.

As the ratio of the rocker arms goes up, the net lift of the valves increase and the valve springs are compressed much closer together. Clearances must be checked to avoid coil bind and contact between the bottom of the valve retainer and top of the valve guide. Springs should have a safety margin of .060" of remaining travel at maximum valve lift to avoid coil bind. The minimum clearance between the retainer and valve guide at maximum valve lift should also be .060". If the minimum clearances are not maintained and the valve spring or retainer bottoms out, the valvetrain will usually bend or break a pushrod. Clearance between the rocker arm and spring retainer must also be checked at maximum lift to make sure they don't touch. The stock rockers on a SB Chevy V8 can handle about .470" of valve lift. More lift requires switching to "long slot" rockers or aftermarket rockers with extra clearance.

High lift aftermarket rocker arms or a high lift cam may require using different springs that allow increased spring travel. Some springs cannot handle a maximum valve lift of more than .550". For higher lifts, different springs are required. Follow the spring supplier's recommendations when matching valve springs to maximum valve lift. Another way to avoid spring bind is to raise the installed height of the valve or to lower the spring seat. But both of these will reduce spring tension, which is not the way to go with a high revving engine.

For small block street performance engines with a flat tappet cam and no more than .450" of lift, single springs with 80 to 90 lbs. of seat pressure with the valves closed are usually adequate. For street/strip performance engines, springs with 100 to 120 lbs. of seat pressure are usually recommended. For street hydraulic roller cams, seat pressure should typically be 105 to 140 lbs., and should not exceed a maximum of 150 lbs. with a mechanical roller cam.

Double or even triple springs are usually required to achieve higher spring pressures. Seat pressures for double springs typically range from 130 to 150 lbs. or higher, and 300 or more lbs. for triple springs. Most NASCAR teams run dual springs with seat pressures of 190 to 200 lbs. and open pressures of 500 to 600 lbs. at .750" lift. Pro Stock drag racers, by comparison, typically run triple springs with seat pressures of 375 to 475 lbs. with the valves closed, and up to 1,000 lbs. open!

Increasing spring pressure increases the rpm and horsepower potential of the engine. Every additional 100 rpm may be worth an extra 20 or more horsepower on a highly modified performance motor. The current limit for steel valve springs is about 83 to 85 cycles per second, or about 10,000 rpm. NASCAR teams run a 200 to 400 mile race at 8,500 to 9,000 rpm. But drag racers only run a quarter of a mile.

High pressure valve springs can deliver the rpms, but there's a price to be paid because the springs don't last. Running at such high rpm wears out the springs. Consequently, the springs have to be replaced fairly often (every race with NASCAR engines, and after so many runs with drag racers).

Higher spring pressures also puts more load on the rocker arms, pushrods, lifters and cam lobes, which increases the risk of something breaking.

According to one major camshaft supplier, standard camshafts can usually handle open valve spring pressures of up to 550 lbs. But for higher spring pressures, a carburized 8620 or 9310 steel camshaft is required.

Installing double springs may require the following modifications:
Flycutting the spring seats in the heads to accept the springs.
Changing the spring retainers to ones that are designed for double or triple springs.
Changing the valve seals and/or machining the guides for extra clearance.
Replacing pressed-in rocker arm studs with screw-in studs and a stud girdle, or installing shaft-mounted rocker arms.
Replacing the stock pushrods with stronger and stiffer 4130 chrome moly pushrods (to prevent pushrod flexing and breakage).
If the springs provide more than 350 lbs. of pressure when the valves are open, the stock stamped steel rockers will have to be replaced with stronger aftermarket steel or aluminum rockers.

Beehive springs that taper towards the top are a hot commodity in the aftermarket, but date back to the earliest days of the automobile. Like shaft-mounted rockers, though, they are finding new applications in todays high performance engines. Chevy LS1/LS7 series engines use a factory beehive spring, as do Ford modular 4.6L V8s. Similar spring designs have been developed for SB Chevy and Ford engines by aftermarket suppliers. Unlike a conventional valve spring that has a constant diameter, a beehive spring tapers in toward the top sort of like a real beehive (thus the name). A smaller top means a smaller and lighter valve spring retainer can be used to reduce weight. Also, the change in the diameter of the spring as it tapers toward the top creates a progressive spring rate that helps the spring resist harmonics that occur in conventional constant rate springs. The bottom line is that beehive springs perform better than conventional single springs on many (but not all) engine applications.

One spring supplier said their beehive springs can increase the rpm potential of an engine 100 to 1,200 rpm depending on the cam, valvetrain and other engine modifications. The maximum amount of valve lift a beehive spring can handle is about .650", so if the engine needs more lift it will require dual or triple springs.

Beehive springs have been popular on the street, but some racers are cautious about using them because there's no safety margin if a spring breaks. With a double or triple spring, the engine won't eat a valve if a spring breaks. The extra springs serve as a backup to pull the valve shut.

Heat is the main enemy of the springs, with dual and triple springs typically generating more heat than single springs because they rub against each other. Managing heat, therefore, is critical for spring longevity.

The durability of a spring depends on the quality and purity of the alloy that is used to manufacture the spring, the heat treatment the spring receives, and any additional surface treatments the spring is given. Some springs are nitrited while others are coated with proprietary chemicals that help the spring run cooler. Another trick that can extend spring life is to have the springs cryogenically treated. Freezing the springs to 300 degrees below zero can increase spring life up to five-fold, according to those who do it.

There are a couple of things to watch when installing valve springs. One is height. This ensures the springs have the required pressure to keep the valves shut. Height is checked by measuring the distance between the spring seat in the head and the retainer on the valve stem. Most performance valve springs are closely matched, but if adjustments are needed it can be done by shimming the valves to equalize pressures. The thicker the shim, the more it increases spring pressure. Don't overshim, though, because doing so may lead to coil bind with a high lift cam or rocker arms.

Shims are made of hardened steel, come in various thicknesses and are usually serrated on one side to prevent rotation (the serrated side faces the head). Some shims are also designed to help insulate the springs from heat generated by the cylinder head. Springs should also be lubricated when they are installed in a new engine, especially double and triple springs, to reduce friction. Soaking the springs in oil or coating them with assembly lube should provide adequate protection during the critical first start-up.

Reducing weight on the valve side of the rocker arm has more of an impact than reducing weight on the pushrod side because of the leverage effect. Lightweight valve retainers made of titanium have long been the preferred upgrade here. But in the past year, the price of titanium has skyrocketed. Most of the world's titanium supply comes from Russia and is being consumed by China. Some aftermarket suppliers have responded to the changing market conditions by introducing new lightweight steel retainers.

For street applications, steel retainers with stock 7 degree locks are usually recommended. But for racing or high rpm roller cams, titanium retainers with 7 or 10 degree locks can reduce weight. Some locks have an extra step inside that reinforces the bottom of the retainer and reduces the risk of the valve pulling through at high rpm. When the valve locks are installed around the valve stem, their edges must not touch each other. They should clamp against the valve stem and hold it securely. Keep in mind that the design of the retainer affects the installed valve height and spring tension.
Last edited by a moderator:
The Truth About Valve Springs (from comp cams)
Valve springs are one of the most critical and most overlooked components in your engine. Proper selection of the valve spring begins with identifying the application and selecting all of the valve train components to achieve the engine builders’ goals.

The spring is selected to complement the system and must be matched with the entire valve train in order for the engine to reach its full potential. It does absolutely no good to install a cam that will rpm to 8000 if you do not have the correct springs. Improper selection of the wrong valve spring is one of the most common causes of engine failure. Other common causes are the incorrect installation and improper handling of the valve springs.

Selecting a Spring
1. Use only the valve springs that will give the correct spring pressure with the valve both on the seat and at maximum lift.

2. The outside diameter of the recommended valve spring may require that the spring pocket of the head be machined to a bigger size.

3. One of the easiest and sometimes most costly mistakes made in racing engines is not positively locating the spring. A valve spring that “dances” around on the cylinder head or retainer causes harmful harmonics and excessive wear. A spring that is forced onto a retainer is likely to fail at that coil. That is why we have such a large selection of steel and titanium retainers, hardened steel spring seat cups and I.D. locators to better match our springs. A spring that is contained properly at the retainer and the cylinder head will offer the longest possible service life.
Proper Spring Handling
1. Handle springs with care. Never place in a vise, grab with pliers or hit them with a hammer. This will damage the surface of the spring, which will cause a spring to fail.

2. When separating double or triple springs, use only a durable plastic object that cannot harm the shot-peened surface of the spring. Never use a tool or hard metal object like a screwdriver.

3. Valve springs are shipped with a rust preventative coating that should remain on the spring throughout engine assembly. Do not clean springs with acidic or evaporative cleaners. This causes rapid drying and promotes the formation of rust on the surface, which can cause catastrophic failures. Even a slight amount of corrosion can grow to be a problem.

4. When installing springs, use COMP Cams® Valve Train Assembly Spray (Part #106) to ease assembly and improve the life of the spring.
Checking Loads
1. COMP Cams® has matched each set of springs for load consistency. A variance of + or -10% is acceptable for new springs.

2. When checking the spring loads on a load tester (Part #5313) measure and note the thickness of the retainer where the outer spring sits. Assemble the retainer on the spring and place on the base of the spring checker.

3. Compress the spring to the desired installed height. This is the measurement between the top of the spring (on the bottom side of the retainer where the outer spring sits) and the bottom of the spring on the base.
* NOTE *
Since the retainer is installed in the spring when checking the spring loads, make certain that the thickness of the retainer is not included when calculating the installed height and is accounted for when compressing the spring. The spring load checker will show to be higher with the spring installed at the correct height.

1. Before installing the spring on the cylinder heads, check the installed spring height (Diagram A). This is the distance from the bottom of the retainer to the surface where the spring rests on the head. The valves, retainers and valve locks will be used in this step. First, install the valve in the guide, then install the retainer and valve locks. Pull the retainer tightly against the valve locks while holding the valve assembly steady.
Measure the distance between the spring seat and the outside step of the retainer using your height micrometer (Part #4928 or #4929) or a snap gauge and a pair of calipers. Repeat this procedure for all the valves and record your Information. After you have measured all the valves, find the shortest height. This will become the spring’s installed height on your heads. If your combination includes a dual or triple spring assembly, it will be necessary to allow for the inner steps of the retainer.

2. Once you have determined the shortest installed height, it will be necessary to use shims to obtain this height (±.020” is acceptable) on the remaining valves. These are available through our catalog or at any of
your local COMP Cams® dealers.

3. Before removing the retainers, measure the distance from the bottom of the retainer to the top of the valve seal (Diagram A). This distance must be greater than the lift of the valve. If not, the guide must be machined. This is a very common cause of early camshaft failure.

4. Once the valve springs have been installed, it is important to check for coil bind. This means that when the valve is fully open, there must be a minimum of .060” clearance between the coils of both the inner and outer springs. If this clearance does not exist, you must change either the retainer or the valve to gain more installed height, or change to a spring that will handle more lift or machine the spring seat for extra depth.

5. Always check for clearance between the retainer and the inside face of the rocker arm. This will be most evident while the valve is on the seat. Rocker arms are designed to clear specific spring diameters, so you should check to see that you have the proper rocker arm/retainer combination. This situation can also be the result of improper rocker geometry and may be corrected with different length pushrods or a different length valve.

6. To aid in the engine breaking process, spray the springs, rocker arms and pushrods with COMP Cams® Valve Train Assembly Spray (Part #106).

Breaking In a Spring

1. It is important for new springs to take a heat-set. Never abuse or run the engine at high rpm when the springs are new. Upon initial start-up, limit rpm to 1500 to 2000 until the temperature has reached operating levels. Shut off the engine and allow the springs to cool to room temperature. This usually will eliminate early breakage and prolong spring life. After the spring has been “broken-in”, it is common for it to lose a slight amount of pressure. Once this initial pressure loss occurs, the spring pressure should remain constant unless the engine is abused and the spring becomes overstressed. Then the springs must either be replaced or shimmed to the correct pressure.
69-CHVL said:
Pretty interesting...let's see how these do.


Progressive frequency increases RPM limit & creates ability to run more aggressive camshafts
Constantly decreasing diameter from bottom to top reduces active mass & decreases applied forces – result is longer valve train component life & less parasitic horsepower loss
Reduced mass improves RPM stability
Conical design is the best natural frequency damping setup – dampens without wear, heat/friction or risk from interference contact
Superfinish surface processing increases both lift capability & spring longevity

Expected to become the new standard in high performance valve spring design, COMP Cams® Conical Valve Springs utilize round wire and feature a diameter and progressive pitch driven natural frequency. This design increases the valve train RPM limit while reducing resonance concerns and decreasing dynamic spring oscillations. The result is longer spring life and the ability to run more aggressive camshafts. A breakthrough in valve spring development, COMP Cams® is the very first to introduce this advanced conical design.


136 @ 1.800 412 @ 1.170

145 @ 1.900 495 @ 1.225

160 @ 1.900 495 @ 1.210

now not having seen several dyno tests , showing any consistent advantage in their use, yet I,m inclined to wait before jumping on the band wagon..
mostly because I know that properly set up dual valve springs. on a properly selected cam, can easily control valves at well over 7500rpm and I rarely build engines designed to operate over that rpm range.
yes Im well aware that some of the European built engines have used these type springs for several years , but the much larger and heavier valves in the larger American V8 engines MIGHT pose a different set of inertial values, the springs may not handle as well.
So Ill wait to see some consistent results using some more adventurous and well funded guys experimentations
I have had sucess using Iskenderian & Crower Valvesprings.
After run in 5# seat pressure lost at most.
Its impossible to analyze new valvesprings without a Spintron , dyno, & real world race testing.
Isky Tool Room Gold & PSI valvesprings excellent if you can afford. $400 a set to start.
Titanium valvesprings have been made.
Pretty exotic. $1k to start for a set.
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.
some roller rocker too retainer combo clearance issues cause problems easily solved with beehive springs and smaller retainer diameters

for several years even stock BBC engines ,(the markVI and mark V) as opposed to the (mark IV earlier BBC engines)
also don,t use adjustable rocker arms if your running a stock cam and valve train with stock O.E.M. heads you probably can get by without them,
swap to a higher lift cam and a longer duration and aftermarket heads and better valve strings and in my opinion,
you would be very foolish to build and use a performance BBC engine without adjustable push rod guide plates
what you really should do is order these
Dart 27001230-4 - Dart Pushrod Guideplates


viewtopic.php?f=44&t=2839&p=7344&hilit=adjustable+guide#p7344 ... /18111.htm

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



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


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





read related info ... gTech.aspx ... g_upgrade/ ... rings.aspx
Last edited by a moderator:
By David Reher, Reher-Morrfison Racing Engines

“The valve spring is like a canary in a coal mine – it will usually signal a developing problem before a catastrophic failure.”

When Galileo pointed his handmade telescope at the planets and became the first human to behold Jupiter’s moons and Saturn’s rings, he saw something that had been invisible. Of course these moons and rings had existed for millenia, but they were beyond human perception until the invention of a device that could magnify the faint images. Like Galileo’s telescope, tools such as dynamometers, wet flow benches, and data recorders have given drag racers the ability to “see” events that would otherwise be imperceptible to human senses.

Recently I had an opportunity to test valvetrain components on Comp Cams’ Spintron, a 21st century tool that is as advanced as Galileo’s spyglass was in the 1600s. A Spintron resembles a dynamometer, but instead of a water brake there is a powerful electric motor that spins the test engine’s valvetrain at high speed. Outfitted with lasers and high-speed video cameras, the Spintron gives cam designers and engine builders the ability to observe and analyze valvetrain components at high rpm.

This wasn’t my first experience with a spin fixture. Years ago my late partner Buddy Morrison constructed a spin fixture for our shop that employed a hulking 460 cid Ford V-8 engine to spin the valvetrain assembly in our test engines. A strobe light synchronized to the engine rpm would “freeze” the motion of the valve and spring. The instrumentation and software that were available at the time weren’t particularly user-friendly, but we did learn a tremendous amount about how springs and valves behaved under actual operating conditions. It was a little disconcerting to see the valves continue to accelerate over the nose of the cam and then free fall as the springs slammed the lifters onto the cam lobe’s closing ramp. Maybe that was more information than I really wanted!

The Spintron can record the 1-inch valve lifts that are now commonplace in Pro Stock engines, and the software can distill the information to an understandable format. I secretly hoped that we’d discover some problems in our Pro Stock valvetrains that we could easily cure and thereby improve performance. It turned out that our valvetrain’s dynamics were reasonably good. We weren’t suffering frequent valvetrain failures, so the Spintron confirmed what I already knew: We had a sound setup that wasn’t overtaxing the components. On the other hand, I also learned that perhaps we could push the limits with a more aggressive camshaft design.

Like the dyno, flow bench, data recorder and other tools of engine development, a spin fixture reveals trends, not ironclad answers. The most important information it provides is the knowledge that the cam and valvetrain components are mechanically capable of running to the intended maximum speed. If the engine won’t rev up to full speed on the dyno or the drag strip, then it’s likely that the problem lies somewhere other than the valvetrain.

A spin fixture can lead you down a dead-end path if you pursue smoothness at all costs. In my experience, an extremely smooth profile is unlikely to win drag races. It might be suitable for a NASCAR stock car engine or an endurance racing application, but a cam usually needs to move the valves more aggressively to win on the drag strip. We don’t race for 500 miles, so our cams and valvetrains can be closer to the edge.

Pushrods are a hot topic among engine builders, and an area that we investigated on the Spintron. There is a trend toward pushrods with larger outside diameters and thicker walls. In our Pro Stock engines, for example, we’re using 7/16-inch O.D. pushrods with .165-inch wall thickness. These pushrods would be overkill in a bracket racing engine, but there are definitely gains to be made by reducing pushrod deflection in all types of competition engines.

No pushrod, rocker arm or lifter is infinitely stiff. They all bend and deflect to various degrees. The goal is to limit this deflection to a reasonable level. A pushrod that bends and rebounds under load will change the effective cam timing at the valve, often in unpredictable ways. All of the parts of the valvetrain are inter-related, and the pushrod should not be a spring in this complex system.

If you’re a serious racer, you don’t necessarily need a spin fixture to evaluate your engine. Valve springs are excellent indicators of valvetrain performance. The valve spring is like a canary in a coal mine; it will usually signal a developing problem before a catastrophic failure – but only if you heed the warning signs. If you install a new cam profile that knocks out 50 pounds of valve spring pressure on one run, you probably have a problem.

Both the Spintron and the dyno have convinced me that a valve spring performs best when it runs in a certain relationship with the cam lobe. Installed height and the distance from coil bind are both critical. In the good old days, we’d set up the valve springs at the installed height that produced the seat pressure we wanted, and then add a .030-inch or .060-inch shim when they lost pressure. I now believe that’s the wrong approach for a high-end racing engine. In a perfect world, the spring should operate at its optimum position from coil bind regardless of its pressure. Valve springs are very complex components; evaluating a spring on pressure alone is like choosing a cylinder head solely on its airflow while ignoring velocity and cross-sectional area.

The advent of commercially available spin fixtures will certainly accelerate the development of better cam profiles and valvetrain components. Just as the science of astronomy has progressed from Galileo’s spyglass to the Hubble Space Telescope, new technology is helping racers to see the invisible.

worth watching, just for the tips on new head inspection
Last edited:
I've been looking at this video over the last couple of days, wondering how do I get from Vizard's
info to a valve spring spec that I can buy !
Sure I could just call Crower to see what they
recommend, but that does NOT help me understand.

The resonate frequency changes with lift, but the valve opening rate changes with RPM, so what RPM do
I base my decision? I've decided to use the maximum RPM for my engine and that would be about 6000
RPM. See the Excel table for the target valve spring resonate frequency of 10 times the valve opening rate.
See video reference #1 for Vizard's statement of 10 times.

Since I'm interested in the Beehive spring, this post will be solely about this option. Which most
street/strip engine valve spring upgrades would be the Beehive spring, the conical spring would be for much
higher RPM engines.

I need a Beehive spring with an installed height such that it's installed height has the spring compressed by
0.600" from it's free height, my cam has a .550 lift. this moves the resonate frequency out to the vertical
part of the graph where the frequency is rising very quickly, although I can't tell where coil bind will take
place. See video reference #3

The valve spring resonate frequency for a standard dual valve spring is 350 Hz to 550 Hz, but a Beehive
spring frequencies are 350Hz to over 1000 Hz if you have the spring in the far right part of the graph.
See video reference #2

Comments Welcome !!!

(Video References Below)
1.) 16:40 – The resonate frequency of the spring should be 10 times higher than the frequency with which
the valve is opened.

2.) 18:20 – Spring resonate frequency of a standard spring is 350 Hz to 550 Hz, Beehive is 350 Hz to >1000 Hz.

3.) 28:55 Beehive spring needs to be installed such that it is within .025” of coil bind.



the last couple cylinder heads I purchased bare, and bought higher quality valve springs, valves etc,
I bought the valve springs from these guys, ask to talk to someone with a tech background
print out your list of tech questions prior to making the call so you don,t forget one.

prior to making the call, know your installed height and seat diameter and valve stem diam, and the type of keepers you have, valve lift, and ask questions about beehive springs

Hydraulic Roller Camshaft: generally use 130-140 lbs Seat Pressure/300- 355 lbs open pressure.
a bit more won,t hurt but remember your current cams

Part Number: 00471S
Chevrolet Hydraulic Roller Camshaft

Chevrolet - 262, 267, 283, 302, 305, 307, 327, 350 & 400
Performance level 4 - High Lift - Street/strip applications, rough idle, 2500 stall required.
INT/EXH - Dur @ .050” Lift: 236°/240° RR: 1.5/1.5 Gross Lift: .555”/.559” LSA: 110° RPM: 2400 to 6000 Redline: 6500

not going to perform all that well past about 6500rpm, and even if you were to change to a comparatively wilder cam

like for instance (which would kill a good deal of street ability in exchange for a bit more top end power)
Im sure you can do a DD2000 software comparison
the valve springs would still work reasonably well, remember the trans shifts below 6000 rpm
Last edited:

I've recently had a few questions on upgrading valve springs, and in many cases were talking about cylinder heads ,
that have either been on the car for over 15 -30 years or of unknown age, like on heads purchased at swap meets or off the internet,
or on a recently purchased muscle car or corvette that is well over 30 years old.
well it's no real challenge, to figure out that if you have to guess, at the valve spring condition and age ,
that at a minimum the valve springs should require testing for load rates and clearances ,
and it probably would be a good idea to swap to new valve seals,
while your testing the valve springs and checking clearances and valve guide wear!
Id have to point out that your original valve springs might have had 120 lbs of seat and 300 lbs of open pressure, but stress is cumulative and after decades of use, those same valve springs will NOT have aged identically , many may now have less than 100 lbs of seat pressure and under 250 lbs of open pressure, several even less!
thus the reason your valves float at a lot lower rpm than you remember from the 1970s-or 1980s when you bought that muscle car, and for sure if its a set of original heads of a car thats been trashed regularly over decades
The following recommendations are from Erson Cams. If you have questions, you can reach their tech department at 800-641-7920.

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 ... ewall.html

related threads
Last edited:

yes I'm well aware that valve spring testers are rather expensive and that most people are reluctant to pull the heads and disassemble the heads so they can bring the valve springs down to a local machine shop, to be tested, as the local machine shop is very likely to tell them what they don't want to hear..."the valve springs really should be replaced as they are no longer up to spec." or as one of my friends said " I've never seen a machine shop that did not want to sell a new set of valve springs and suggest you really need a valve job if the springs are worn, so its a foregone conclusion, that they will suggest your old springs are worn and need replacing, I really don't want to pay them an extra $100 to hear what I know they are going to say about my cars valve springs"

related info you really need to read
Last edited: