377 or 406

[mtrhead]

Hi,
Newbie here. I have a 69 Camaro (Z28) no motor. New TKO600 2.87 first gear New 3.90 rear (moser 33 spline) Equivalent to at least 4:88 gears of the old days. I desire to (will) have the Crossram setup. Probably a Edelbrock STR10 or the OFFY

So, the question is. I'm planning on going with a SHP 4.155 block. I know displacement but I love RPM which either combo can realistically give. Heads will be 210 Pro-Filers with a solid roller cam. Compression will be 11:5 to 1. All street driven. Good gas, race gas mix. Thoughts on my build? Do I go 3.48 stroke or 3.75 stroke??

 

[grumpyvette]

both options will have their backers, and both offer advantages, theres little question that a correctly built 406 can produce a bit more torque, or that the 377 can spin up about 400rpm higher in the rpm band,before piston speeds become critical, and in the old days its was almost a total no brainer in that the 377 sbc would produce more hp per cubic inch simply because the heads available at the time would become very restrictive at high rpm levels effectively negating the extra high rpm power potential of the 406 sbc engines extra displacement, but in recent years the cylinder heads available have dramatically improved and shifted the potential power curves, and the 406 holds a significant advantage, in both low rpm torque and in high rpm power PROVIDED THE CORRECT CAM,COMPRESSION RATIO AND HEADS ARE USED
it makes very little sense to install a high flow intake manifold and cam or cylinder heads without the other components having nearly equal flow potential or ability to operate in the same rpm range, some of the worst (DOGS) are the result of an engine built with killer intake, manifolds and a cam matched to restrictive heads, or the wrong rear gearing or a restrictive exhaust. but get everything matched and youll be amazed at the results
Ive used both the edelbrock and offy cross rams, ID strongly suggest the OFFY

read thru these threads below carefully

theres a few related threads, with info youll want to read
viewtopic.php?f=55&t=444&p=547&hilit=offenhauser#p547

viewtopic.php?f=55&t=1468

http://www.camaro-untoldsecrets.com/art ... ossram.htm

http://coloradohotrodparts.com/Offenhau ... Y-5901.htm

viewtopic.php?f=87&t=2045&p=5455&hilit=crossram#p5455

viewtopic.php?f=32&t=511&p=636&hilit=crossram#p636

 

[mtrhead]

Point taken on both. Thank you very much for the answers. I have another question
since you favor displacment.

I've had bad experiences with pistons with the oil support rings. (mid 90's) Have things improved? because I can buy a 3.875 stroke crank with 6.0 rods for the same price as the 3.75 with 5.7 rods. Mahle pistons for either. I'd like to go most cubes based on your points which I figured were true. Can I have an oil burning free setup with support rings? (pistons were the pins intersect the ring groove) I could easily build a 427 for the same price. Pro-Filer heads are available in 210, 220, and 245 (too big I think)

Also, thanks on the manifold. Offy's can still be bought new so I wont have to worry about bidding on ebay or craigslist for the Edelbrock.

 

[grumpyvette]

longer 6" rods with the longer 3.875" stroke push the piston pin location too high in the piston for what Id personally consider the ideal upper piston ring land support spacing, between the rings and while it allows you to use a lighter piston its a trade off.
Ive used lots of 6" rods and 3.75" stroke crank kits with support rail rings,and those work ok, but I prefer the 5.7" rod and non-support rail rings in street engine builds for long term durability.
yes you can build a 3.75", or 3.875" or even a 4" stroke crank in the DART aftermarket blocks, something a stock 400 block won,t handle nearly as well from a strenght perspective as the castings far weaker, but I don,t see a significant gain in hp with displacements having a bore size over about 4.155" or strokes over about 3.875" , as the trade off starts to give some durability, and less secure cylinder head gasket seal, in exchange for the hp gained
ID suggest no more than a 5.875" rod with a 3.875" stroke crank, and yeah, you can get almost any piston you want from J&E, KB, PROBE, matched to a good internally balanced scat forged crank and 5.7", 5.875", or 6" rods if you really look carefully

heres some good info threads to read thru

viewtopic.php?f=51&t=2229

viewtopic.php?f=55&t=1468

viewtopic.php?f=51&t=47

but before you dive head first into the project ID like you to think thru your goals, if your looking to build a nice 500-570hp SBC than your going to be doing fine, going this route, but if your thinking of 600 plus hp ID strongly suggest you start thinking about building a 540-556 cubic inch BIG BLOCK COMBO as in the long run the price will be very similar and the BBC has a good deal more performance potential and stronger parts, its a whole lot easier to build a 600hp plus bbc than a sbc , and that extra displacement makes a huge difference
lets assume either engine makes 1.4hp per cubic inch, a 434sbc making 600hp will cost your about $10k so will a 540 bbc, but at 1.4hp per cubic inch the 540 bbc would be at 750 plus hp


http://www.ultrastreet.net/engines/434_ultrastreet.asp

* Horsepower
* Torque
* Bore & Stroke
* Compression Ratio
* Fuel Requirement

* 595 @ 6300 RPM
* 565 @ 4500 RPM
* 4.155 x 4.000
* 10.5 to 1
* 92 Octane
$9950


http://www.ultrastreet.net/engines/540_realstreet.asp

BBC



http://www.summitracing.com/parts/DRT-3 ... /?rtype=10

Have Been Asking For!

* Horsepower
* Torque
* Bore & Stroke
* Compression Ratio
* Fuel Requirement

* 625 @ 5800 RPM
* 640 @ 4000 RPM
* 4.500 x 4.250
* 9.75 to 1
* 91 Octane
$9750

http://www.ultrastreet.net/engines/540_ultrastreet.asp
* Horsepower
* Torque
* Bore & Stroke
* Compression Ratio
* Fuel Requirement

* 695 @ 6300 RPM
* 665 @ 4500 RPM
* 4.500 x 4.250
* 10.5 to 1
* 92 Octane $10,750

 

[mtrhead]

You stated: Ive used both the edelbrock and offy cross rams, ID strongly suggest the OFFY

Why? there are many Edebrock STR10's available right now at a decent price. What is the down fall to getting the edelbrock?

Thank you,

 

[grumpyvette]

both intakes work ok, but only the OFFYs currently in production and readily available NEW,and Ive had better results from the offy equipped engine combos, now I can,t see any real disadvantage to using an edelbrock and if I could still buy new Sy1 (smokey ram intakes) that's the intake base design ID prefer to work with over both the offy and other edelbrock cross ram designs,
you might also remember that many used intakes of that age have been machined or have corrosion damage

http://garage.grumpysperformance.com/index.php?threads/ford-boss-302-vs-chevy-dz-302.16075/

 

[mtrhead]

Thanks - at the end of the day I will probably have a smoke ram. But for now I'm bent on building a clone Z/28 406cc motor for my 69 Z/28

have you ever seen anyone running duals on a smoke ram? (custom lid)

 

[grumpyvette]

Im sure its been done, but the SY1 with a custom lid has less surface area and it makes positioning the dual carbs and matched required linkage a real P.I.T.A. so most guys just go with an OFFY, its simply far easier to go with a good and know effective factory design than to go thru the custom and expensive process for minimal gains if any

you may want to read thru these

viewtopic.php?f=55&t=1468&p=6357&hilit=offy#p6357

viewtopic.php?f=55&t=444&p=5682&hilit=+dual+quads#p5682

viewtopic.php?f=44&t=623&p=834&hilit=+crossram+cross+ram#p834

BTW
assuming your willing to put up with a lumpy idle and less than ideal street manors until your engine hits about 3400rpm
the 406-427 SBC engines at about a 10.5:1 cpr
with a cam that falls in the rane of the crower 00471-that is about as small as you would want to , up to about the lunati 60113,
http://www.summitracing.com/parts/LUN-60113/
afr 210cc heads
http://www.summitracing.com/parts/AFR-1054/

and a 3000rpm stall ,
and an intake like the holley intake
and full length headers

http://www.summitracing.com/parts/HLY-300-110/
and a decent 750cfm-800cfm carb,
and an intake like the will be a really nice performance combo
IF its in a fairly light car with a 3.73:1-4.11:1 rear gear ratio.

 

[mtrhead]

Thank you,
I picked up the Edelbrock STR10 real cheap and it's real nice. So later this year when I get closer on the engine portion of the build I will post more for help for camshaft recommendations. (406 SBC)

Next question would be...My searches on crossrams have resulted in two 600 Holley double pumpers to be the first choice. Since you have built more than "1" of these combo's what carbs so I be searching for?

Direction on everything so far is:
406 / 210cc Pro-filer heads / 11:1 Mahle's with 5.7 rods / 5 speed with 2.89 first TKO600 / 3:90 rear gear / 69 Camaro

 

[grumpyvette]

your combo sounds reasonably well thought thru, Id suggest this cam, or something similar as that cam worked really well in those cross ram engines similar to what your building.
remember youll want to be a bit conservative to maintain some street manors
don,t forger decent roller rockers and a rocker stud girdle

cranes gold roller rockers are decent quality rockers for a small or big block chevy,Ive used those, ERSON, CROWER and COMP CAMS ROLLER ROCKERS, many of them come with jam nuts that require a 3/16" allen key
and look a great deal like these posted here below

but these are NOT locking jam nuts designed to work with a rocker stud girdle

http://www.summitracing.com/parts/tfs-3 ... /overview/
BTW.IF YOUR BUILDING A SBC
http://brodix.com/heads-2/small-block-chevrolet-compatible-heads/ik-series
http://www.jegs.com/i/Brodix/158/1021001/10002/-1

brodix ph# 1-479-394-1075 (ALWAYS VERIFY PART NUMBERS SEVERAL,
TIMES FROM AT LEAST TWO SOURCES, BEFORE ORDERING PARTS)
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

rocker stud girdles require significantly longer shank jam nuts , but you need to mount the rocker stud girdle up out of the way so the upper surface of the rockers can,t touch the lower surface of the stud girdle at full lift
http://www.cranecams.com/?show=browsePa ... e=camshaft

WHY A STROKER
building your average hot rod SBC,figure on an average of 1.1-1.2 horsepower PER CUBIC INCH of displacement
so a 406 (slight clean up bore on a 400) vs building a 355-377-383
should result in an average hp advantage of about 25-30hp for your 383-vs-406
but your peak hp on a 355-377-383 can be very similar to a larger 406 if the components selected are carefully matched the displacement and rpm range of the combo,but theres almost always a very noticeable advantage in AVERAGE torque and average horsepower that will almost always show a marked advantage going to the larger displacement engine.
if youve got a 400 block you currently tend to build a 406 vs a 377 , the 377 used to be the better choice simply because in the past the only source for heads was ported O.E.M. casting, based cylinder heads, being available that could not effectively flow enough air to feed a 406 spinning up at 6500rpm, but in the last 20 years aftermarket heads have improved a great deal, so the larger displacement is now usable and building a 377 vs a 406 rarely makes sense, unless your running under some cubic inch to weight formula on your race car
you also want to keep in mind the limitations of valve train control and piston speed, both factors tend to make building a larger and slightly slower rotating combo the easier route to any given horsepower levels.
or put a different way, its generally easier to build a durable 406 that makes 450hp than a 355 that does so, and its unlikely the 355 will produce near the same average, low and mid rpm torque curve so the 406 tends to be a better street car engine.
people tend to build 383 strokers simply because 400 blocks are harder to locate, as theres easily 10 350 blocks for every 400 block out in the market,and its long been understood that a 383 built with similar components will have a power advantage over a similar 355 combo, and with the popularity or the 383 stroker kits being rather high the cost of 383 kits has come down to the point that the cost difference if your starting from scratch is minimal

 

[grumpyvette]

assuming your driving this car on the street....your combo sounds reasonably well thought thru, Id suggest this cam, or something similar as that cam worked really well in those cross ram engines similar to what your building.

don,t forget decent roller rockers and a rocker stud girdle, and a baffled 7-8 quart oil pan as an engine that will rev like that needs dependable lubracatiion


http://www.cranecams.com/?show=browsePa ... e=camshaft

 

[mtrhead]

Thanks - I have my heart set on a Mechanical Roller cam to get the lift to get all the benefits from the pro-filer heads. They flow awesome into the .600 range so I was looking at Mechanical Rollers to get me there. What are the important specs of the cam you recommened with respect to the crossram?
lobe centerline? duration? overlap?
Got any ideas on a good mechanical roller? I was looking at the Voodoo's and the Crower street rollers.

 

[grumpyvette]

Id suggested the flat tappet solid design because, most guys using a cross ram want to remain "time period correct" and keep costs low.


heres what Id use in the car for street use if I was using a solid roller cam, but why not call crane, crower, isky and Erson cams and get their input/advice
back in the late 1960s and early 1970 most of us were gullible enough to actually believe, most of the magazine engine build results were legit, and when some racer promoted the cam he used many guys figured that was all they needed, to add to their stock 302 z28 to run those track times, after all we had been told it was basically a track car,, it took awhile for the smarter guys to figure out that what you were told was in an engine and what actually was in an engine might be vastly different.
brownfield heads, crane fireball ported heads, etc were all just starting to be used.
I still remember seeing a "stock" 1964-1965 GTO (built and run by a local dealership)run 12.2 second times (only to find out a few years later that the "stock" 389 was a 12.5:1 cpr 421, with an acid dipped hood, front fenders ,trunk, and stripped interior)

Standard 302 (30-30) cam, P/N 3849346
Casting #3849347
254 duration @ .050" (intake & exhaust)
.485" lift (with 1.5 rockers)
114 deg. lobe separation
Exhaust Max lift @ 116 deg. BTDC
Intake Max lift @ 112 deg. ATDC

First Design Off-Road cam, P/N 3927140
Casting #3927141
Intake 257 duration @ .050" (333 advertised)
Exh. 269 duration @ .050" (346 advertised)
Lift: .493" intake, .512" exhaust
Intake Max lift @ 108 deg. ATDC
Exhaust Max lift @ 116 deg. BTDC

2nd Design Off-Road cam, P/N 3965754
Casting #3965751
Intake 248 duration (324 advertised)
Exh. 267 duration (334 advertised)
Lift: .512" intake, .535" exhaust





back around 1969,we used to buy those cams for $47 each at the Chevy parts counters, matched lifter sets we $38 they sounded great,but they were designed for road racing not drag racing,and we found that there were better designs for drag racing cams
but we soon found the faster cars were running a CRANE 110921 in heavy cars with 3.90:1-4.11:1 rear gears and for lighter cars with a 4.56-4.88:1 rear gear the 110981(back then they were called something else, before crane changed their part numbers)

if your convinced you need a hydraulic lifter cam this crane 110711 gives reasonably good performance in a 10.5:1-to-11:1 compression 383 built to similar specs

both cams really require a 350-383 displacement with about 10.5-11.5:1 cpr, headers and a decent intake to run effectively

you might want to read thru these

viewtopic.php?f=55&t=3431&p=9088&hilit=crossram#p9088

viewtopic.php?f=87&t=1938

viewtopic.php?f=55&t=444&p=10794&hilit=+dual+quads#p10794

viewtopic.php?f=32&t=511&p=636&hilit=corvette+crossram#p636

BTW if you do decide to build a 302 displacement engine, getting the engine compression up in the 11.5:1 range and using some mildly ported vortec heads, with bigger valve springs, better clearance, and 1.6:1 roller rockers, with a matching vortec single plane intake and a crane 110921 flat tappet solid lifter cam,and a manual transmission, with a 3.9:1-4.56:1 rear gear ratio, and a good 7-8 quart baffled oil pan has repeatedly proven to make a decent combo in a fairly light car

Hi guys, I am looking at purchasing the 508HP Blueprint Engines 400 Long Block. This engine comes with Blueprint aluminum heads which have a 220cc intake port and a 64cc combustion chamber which puts compression at 10.3:1

I have a new set of AFR 195 Eliminator heads with a 65cc combustion chamber. Below are the flow numbers for the blueprint heads that come on the motor vs my AFR 195's.

The AFR's seem to outflow the blueprint heads by a fair bit and use a smaller intake runner. Given this information if everything else was left the same do you think I would make a lot more power with the AFR heads?

Cam Specs for the Engine
Cam Specs:

Cam Type: Roller
.555 Intake .576 Exhaust
236 Intake / 242 Exhaust duration
@ .050 - 110° lobe separation
With 1.6 Roller Rockers



Intake

Intake Runner Volume (cc): 220cc
Intake Port Location: Standard
Intake Valves Included: Yes
Intake Valve Diameter (in): 2.08 in.
CFM Port Flow Average @ 28"
.100" - 76
.200" - 137
.300" - 189
.400" - 228
.500" - 254
.600" - 258


Exhaust

Runner Volume (cc): CNC- 65cc
Exhaust Valve Diameter (in): 1.600 in.
Exhaust Valves Included: Yes
Port Shape: Square-Port
Exhaust Port Location: Standard
CFM Port Flow Average @ 28"
.100" - 112
.200" - 155
.300" - 186
.400" - 203
.500" - 208
.600" - 216

(NOTICE THE SPECS ARE SIMILAR TO CROWERS 00471)