gm cylinder head cc sizes [Archive] - Team Camaro Tech

: gm cylinder head cc sizes


machi
Mar 5th, 09, 03:56 PM
every thing i look up for the many different heads i got dont tell me cc size of the stock heads, ive also been told that the 2.02 heads with id # 3917291 are "turbo" heads ,not sure what they ment by this?? can any one help??

pdq67
Mar 5th, 09, 04:07 PM
Try here even tho it's not complete!

http://www.chevytech.com/

pdq67

Vintage 68
Mar 5th, 09, 04:27 PM
... also been told that the 2.02 heads with id # 3917291 are "turbo" heads ,not sure what they ment by this?? ... ??

They mean you should be impressed an pay them Big $$$ for them :thumbsup:
That, or they don't know $tuff about Chevy heads ;)
There is no such thing as a '291 "Turbo Head" - these will not fit Corvairs, the only car manufactured by GM with a turbo that year...
The '291 is a 1968 (year model) casting only. Corvairs used "Turbo" mufflers, carbs, pistons and lots of other "turbo" parts l:)
It looks nearly identical to the '461-462 castings used the year before, but it has a flat boss on the side between the single left exhaust port and the center two ports. This boss is drilled and tapped for a Temp. Sender on the 1968 models (moved down from the intake manifold).
The chamber CC is usually in the 63~65cc range from the factory - but they can vary a bit more on some and it is also normal to find them smaller now as many heads you'll find have been 'milled' over the years reducing them.

These are commonly called "Camel Hump" heads :yes:
This refers to the two 'humps' on the front pad of the head...

These came in both 1.94" and 2.02" intake valve size.
The 'factory' heads have a "fly-cut" relief machined around the chamber intake valve area to unshroud the valve.

Here is a quick 'cheater' list of common head CC and valve size(s):
(cast # - CC - Intake - Exhaust)
032 70cc 1.72 1.50
034 64cc 2.02 1.60
041 63cc 1.94 1.50
041 64cc 2.02 1.60
049 55cc 2.02 1.60
056 56cc 1.72 1.50
064 67cc 1.72 1.50
113 58cc 1.94 1.50
116 60cc 1.72 1.50
185 70cc 1.72 1.50
186 63cc 1.94 1.50
186 63cc 2.02 1.60
187 64cc 2.02 1.60
188 75cc 1.72 1.50
291-1 63cc 1.94 1.50
291-2 64cc 2.02 1.60
293 75cc 1.72 1.50
306 56cc 1.72 1.50
316 76cc 2.02 1.60
339 75cc 1.72 1.50
414 64cc 2.02 1.60
441 76cc 1.94 1.50
460 69cc 1.72 1.50
461 62cc 2.02 1.60
461x 62cc 1.94 1.50
462 62cc 1.94 1.50
462 63cc 2.02 1.60
465 60cc 1.72 1.50
480 69cc 1.72 1.50
482 75cc 1.72 1.50
487 75cc 1.94 1.50
487x 75cc 2.02 1.60
492 64cc 2.02 1.60
493 76cc 1.94 1.60
520 61cc 1.72 1.50
523 67cc 1.72 1.50
537 69cc 1.72 1.50
539 60cc 1.72 1.50
545 76cc 2.02 1.60
549 69cc 1.72 1.50
550 60cc 1.72 1.50
554 70cc 1.72 1.50
598 76cc 1.94 1.60
624 76cc 2.02 1.60
682 69cc 1.72 1.50
684 75cc 1.72 1.50
692 60cc 1.72 1.50
754 60cc 1.72 1.50
762 56cc 1.72 1.50
770 60cc 1.72 1.50
772 69cc 1.72 1.50
775 75cc 1.72 1.50
881 76cc 2.02 1.60
882 75cc 1.94 1.50
896 60cc 1.72 1.50
916 76cc 2.02 1.60
991 75cc 1.72 1.50
993 75cc 1.94 1.50
993 75cc 2.02 1.60
997 76cc 1.94 1.60


Hope this helps...

pdq67
Mar 6th, 09, 07:01 AM
Fwiw, my virgin chambered big valve -461's cc'd at 66.0 and 66.+ cc's!!

And you forgot the -601's that can be as small as 52 cc's!

My -601's cc'd at 53 and 55.

And my old trough sparkplug chambered '56, 265, -306 heads chambers cc'd at 60 cc's and 118 to 120 cc intake port size!!

This is why the old 283 Power-Pack head was such a winner on a 283 b/c their intake ports are right at 137 cc's or so, way bigger than the earlier heads dinky ports!

pdq67

Vintage 68
Mar 6th, 09, 11:24 AM
... And you forgot the -601's that can be as small as 52 cc's!

pdq67

I left a bunch of them off the pocket list Paul, because I'm seldom interested in them if I see them at swaps and etc...
You'll notice loads of the 'light-weights', like the '883, aren't on there either - they are just to junky/iffy to even consider buying ;)

Feel free to edit the list with your favorites :yes:

pdq67
Mar 6th, 09, 03:13 PM
No, not at all, the -601's are to me, dandy lightweight casting heads for little engines!

pdq67

OAKLYSS
Mar 8th, 09, 09:55 AM
Yes youngsters, there is a "Turbo" head for SBC. An over the counter only part. Part # 3965784, casting number 340292. Developed in 1975, the best SBC head of the era. "Turbo" is the nickname, like "Powerpack" or "Fuelie" is. They have 14mm angle plugs, 2.02, 1.60 valve seats, no heat riser, large ports, 66cc chambers, screw in studs, new design inlet port floor, large valve spring pockets, Tin alloy added. I have owned a couple pairs before.

67 Plum
Mar 8th, 09, 11:11 AM
Yes youngsters, there is a "Turbo" head for SBC. An over the counter only part. Part # 3965784, casting number 340292. Developed in 1975, the best SBC head of the era. "Turbo" is the nickname, like "Powerpack" or "Fuelie" is. They have 14mm angle plugs, 2.02, 1.94 valve seats, no heat riser, large ports, 66cc chambers, screw in studs, new design inlet port floor, large valve spring pockets, Tin alloy added. I have owned a couple pairs before.

They are angle plug also?

OAKLYSS
Mar 8th, 09, 12:54 PM
They are angle plug also?

Yes, that is what I said. These were Chevys top racing heads until the Bowtie line came out.

Vintage 68
Mar 9th, 09, 12:44 PM
Yes youngsters, there is a "Turbo" head for SBC. An over the counter only part. Part # 3965784, casting number 340292...

Gee, then why don't we just throw Low Port, Mirror Port, "Canuk's", R.Flow, 9C1's, GTZ's, SB2.2's, and maybe even them "Roll-Overs" names at him also :sad:
That will really help answer the question he asked...

He asked a question about a single head number 3917291.

His question was;
... ive also been told that the 2.02 heads with id # 3917291 are "turbo" heads ,not sure what they ment by this?? can any one help??

I answered THAT question;

... There is no such thing as a '291 "Turbo Head" - these will not fit Corvairs, the only car manufactured by GM with a turbo that year...
The '291 is a 1968 (year model) casting only...

Hope this helps...

I didn't try to 'confuse the issue with facts' about what some other GM heads are refered to - by some.
Specially some of the low-production "over-the-counter" units sold only for a few years...
I highly doubt that one GM/MTG employee's in the 70's would ever refer to those heads by that name anyway - none I ever talked to did when they were supplying me with them :noway:
Oh, btw - only the post 1976 production '292's have the higher 'tin' alloy content (this helped with the head gasket failures by strengthening the deck section), the earlier versions don't ;)
You also forgot to mention the need for different head bolt lengths at some locations vs. standard heads - but, folks that build performance engines would know this...

These were Chevys top racing heads until the Bowtie line came out.
Most folks building performance engines using GM heads still prefered the earlier '746' 'Raised Plug' head for high compression engines - prefering the stronger deck over smoother port flow (unported) for engine longevity.


:D My wife did get a kick out of the "youngsters" comment though :thumbsup:
She told me "don't let it go to your head" though :o