1967 SB cylinder heads part two

[Donald O.]

What is/was the volume of the intake ports?
170cc
180cc
190cc
???

Something else?

DonO

[Donald O.]

Re: 1967 SB cylinder heads part two

Also, does anyone offer the 0.015" steel shim head gasket for a 327? or just the 350?

[Joe L.]

Re: 1967 SB cylinder heads part two

Also, does anyone offer the 0.015" steel shim head gasket for a 327? or just the 350?

Don------


Actually, a 327 and 350 head gasket are essentially the same. I believe the Fel-Pro 7733SH1 is a 0.015" steel shim head gasket. Also, if you could find NOS GM #3830711 it would be what you seek.

[Patrick H.]

Re: 1967 SB cylinder heads part two

Don------


Actually, a 327 and 350 head gasket are essentially the same. I believe the Fel-Pro 7733SH1 is a 0.015" steel shim head gasket. Also, if you could find NOS GM #3830711 it would be what you seek.

Joe,

The 3830711 appears to still be available. If nothing else, a Google search shows lots of places that allegedly sell it.
Is the current one different from the originals?

Patrick

[Jack H.]

Re: 1967 SB cylinder heads part two

Since nobody else has commented about intake runner volume...

Going mostly from memory, I believe the 1967 #3890462 heads to have the smallest intake volume of any of the camel-hump heads. I wanna say it is down in the 160cc range....162cc rings a bell, but again, going from memory.

Hopefully somebody else has a definitive number, but wanted to chime in since there were no replies on that question so far.

[Joe L.]

Re: 1967 SB cylinder heads part two

Joe,

The 3830711 appears to still be available. If nothing else, a Google search shows lots of places that allegedly sell it.
Is the current one different from the originals?

Patrick

Patrick------


You're correct. It is still available from GM; I thought it was discontinued, but it's not. However, looking up the specs on this gasket it looks like it's 0.026" thick. I don't recall any original steel shim gaskets that were this thick, so maybe this is a SERVICE-only gasket. It's a part number that dates back to 1963, though.

[Donald O.]

Re: 1967 SB cylinder heads part two

Since nobody else has commented about intake runner volume...

Going mostly from memory, I believe the 1967 #3890462 heads to have the smallest intake volume of any of the camel-hump heads. I wanna say it is down in the 160cc range....162cc rings a bell, but again, going from memory.

Hopefully somebody else has a definitive number, but wanted to chime in since there were no replies on that question so far.

I too have been unable to find any definitive answer to the runner volume.....yet.
DonO

[Jack H.]

Re: 1967 SB cylinder heads part two

I too have been unable to find any definitive answer to the runner volume.....yet.
DonO

I looked in a couple books that I have and didn't find anything regarding runner volume.

FWIW, Alan Colvin's 'Chevrolet By The Numbers 1965-1969' book only says that the combustion chamber volume is 62.076cc for early 462's and 63.305cc for later 462's. That's probably where I got my 162cc above, i.e. I was thinking of the 62cc combustion chamber instead...so disregard my earlier comment/guess.

[Duke W.]

Re: 1967 SB cylinder heads part two

The 462 inlet runner is about 160 cc - same as most other "big port" heads other than the '61-'63 461X, which are about 172. 462 head chamber volume with the 1.94/1.2" valves is about 62 cc, which is about 1-2 cc larger than 461X and 461 because the small quench zone on the spark plug side of the cylinder was beveled away with the new mold geometry. I'm not aware of any difference between "early" and late". Add 2-3 cc for 2.02/1.6" valve sets on any heads due to the inlet unshrouding machining operation.

Felpro offers a polymer coated .015" shim gasket, part number 1094. Though the ...711 is speced at .026" a set I measured was .022", and it's also stamped MC6631, so a McCord 6631 is the same part without the GM part number stamp.

Duke

[Jerry G.]

Re: 1967 SB cylinder heads part two

Are the 292 heads essentially the same as the 461 heads?

[Donald O.]

Re: 1967 SB cylinder heads part two

The 462 inlet runner is about 160 cc - same as most other "big port" heads other than the '61-'63 461X, which are about 172. 462 head chamber volume with the 1.94/1.2" valves is about 62 cc, which is about 1-2 cc larger than 461X and 461 because the small quench zone on the spark plug side of the cylinder was beveled away with the new mold geometry. I'm not aware of any difference between "early" and late". Add 2-3 cc for 2.02/1.6" valve sets on any heads due to the inlet unshrouding machining operation.

Felpro offers a polymer coated .015" shim gasket, part number 1094. Though the ...711 is speced at .026" a set I measured was .022", and it's also stamped MC6631, so a McCord 6631 is the same part without the GM part number stamp.

Duke

Is this why porting gives good HP results at the upper rpms?

Thanks for the FelPro part number.

DonO

[Joe C.]

Re: 1967 SB cylinder heads part two

What is/was the volume of the intake ports?
170cc
180cc
190cc
???

Something else?

DonO

approximately 160cc. All of the Double Hump heads were about 160-162 cc, except the "X" heads which were about 170 cc. I measured my 461's at 162cc, and ported them to 183cc. The 327 they were installed on made about 425 flywheel HP with them.

FelPro has a coated steel gasket:

http://www.summitracing.com/parts/fel-1094?seid=srese1&gclid=CPuFyLrB7sMCFdgNgQodB5EA9w

[Duke W.]

Re: 1967 SB cylinder heads part two

Not really. The purpose of massaging the heads as part of an OE engine restoration is to increase the isentropic flow coefficient, which only requires removal a a few cc of material in critical areas. It's the improved flow coefficients that add 10-15 percent more top end power and 500-1000 more useable revs using an OE camshaft, carb, manifolds, etc. so the engine looks correct and has the OE configuration idle behavor.

See the Fall 2010 Corvette Restorer: "A Tale of Two Camshafts" for a more detailed explanation and data.

Duke