1967 Small Block Steel Shim Head Gaskets

[Rocco S.]

I have a question on OEM Steel Shim Head Gaskets. I have a 1967 with L79 Sp Hi-Perf (327-350) engine.

I looked up the correct head gasket number in my Chevy Parts Boo and found 2 listings with different numbers. Which one is most correct and pass flight judging?

1. # 3931606 57-68 Corvette 283, 327
2. # 3930711 55-72 Corvette 265, 283, 327 350

Did # 2 supercede #1?
Are these still available from the dealer?

Thank You

[Rocco S.]

Re: 1967 Small Block Steel Shim Head Gaskets

CORRECTION

#2 should be # 3830711

Sorry for the typo

[Alan D.]

Re: 1967 Small Block Steel Shim Head Gaskets

3931606 rep 3819424 on 11-68 then in 09-79 back to use 3931606
3830711 did not find a replacement history, but used ALL over GM
Ref: GMPartsWiki.com

I would just use a good gasket, however wait for experts to chime in.

[Joe L.]

Re: 1967 Small Block Steel Shim Head Gaskets

CORRECTION

#2 should be # 3830711

Sorry for the typo

Rocco------

GM #3830711 is still available and is what you are looking for. You could also use a Fel-Pro #7733SH1. No one will know the difference.

Caution, though: for a steel shim type gasket to seal properly, the cylinder head and block surfaces have to be absolutely flat and true. Are you certain yours are?

[Duke W.]

Re: 1967 Small Block Steel Shim Head Gaskets

Your engine was originally built with a .018" shim gasket that was never available through service parts. The ...711 is .026" because GM assumed that if a dealer removed heads for service they would be surfaced, and they didn't want the engine to get into detonation.

What are you trying to accomplishi? Are the heads off? What type and thickness head gasket did you find? Are the pistons the OE type forged with a .125" dome?

Head gasket thickness is a very important to compression ratio. Ten thou is about half a point. You don't want to go too high for your available fuel, but there's also no point in leaving performance and fuel economy on the table by dropping the CR too much.

Duke

[Rocco S.]

Re: 1967 Small Block Steel Shim Head Gaskets

Thanks for all the responses. The reason for my question is that I recently saw NOS ...711 gaskets for sale on eBay. My car only has 54K miles (L79) and runs fine. But I know some day the engine will need to come apart for one reason or another. Based on that I have been searching/buying NOS engine parts when available. I already have an NOS ...351 Cam, lifters, rocker arms (TRW), timing chain & sprockets, intake gaskets and oil pan gaskets. Still need head gaskets, oil pump and correct valve springs.
I find it a challange to find NOS parts at reasonable prices. I feel the money spent now is wise investment as GM isn't making these parts any longer and they won't go down in price.

I know I can get all this stuff in the aftermarket but don't trust the quality. The car is a 2 time chapter top flight and a survivor. Possible Bowtie candidate so keeping it as original as possible is my goal.

[Joe L.]

Re: 1967 Small Block Steel Shim Head Gaskets

Thanks for all the responses. The reason for my question is that I recently saw NOS ...711 gaskets for sale on eBay. My car only has 54K miles (L79) and runs fine. But I know some day the engine will need to come apart for one reason or another. Based on that I have been searching/buying NOS engine parts when available. I already have an NOS ...351 Cam, lifters, rocker arms (TRW), timing chain & sprockets, intake gaskets and oil pan gaskets. Still need head gaskets, oil pump and correct valve springs.
I find it a challange to find NOS parts at reasonable prices. I feel the money spent now is wise investment as GM isn't making these parts any longer and they won't go down in price.

I know I can get all this stuff in the aftermarket but don't trust the quality. The car is a 2 time chapter top flight and a survivor. Possible Bowtie candidate so keeping it as original as possible is my goal.

Rocco------

As I mentioned, the GM #3830711 head gasket is still available from GM. So, you don't need to look for "NOS" examples on eBay (unless you can get them for less money than from a GM dealer where they're about $15 each GM list).

Also, the valve springs for your application are still available from GM. They're GM #3911068. Once again, no need to find "NOS" examples on eBay (unless you can get them for less than their current GM list price of about $12 each, GM list).

You should understand, though, that neither of the above parts are now or were ever manufactured internally by GM. They are manufactured by OEM suppliers to the automotive industry. Those suppliers can change over time. Sometimes, those suppliers also sell into the automotive aftermarket under various brands. However, there is no guarantee that the parts they sell into the aftermarket are the same as those they supply to OEM------sometimes they are and sometimes they are not.

[Rocco S.]

Re: 1967 Small Block Steel Shim Head Gaskets

Joe,
Thank you for your response which included the valve spring part number. I understand that GM does not manufacture these parts any longer and just out-sources them and puts them in GM boxes. But buying GM parts you are assured (hopefully) they meet the original GM specifications.

I happened to stop off at a local Chevy dealer yesterday and asked the parts guy for prices on the gasket and springs. I was shocked the prices he quoted:

3830711 Head gasket $34.16 each
3911068 Valve Spring $23.27 each

Sounds like he took the list price and doubled it! Obviously I did not place an order. I will try another Chevy dealer where I get realistic prices.

[Joe L.]

Re: 1967 Small Block Steel Shim Head Gaskets

Joe,
Thank you for your response which included the valve spring part number. I understand that GM does not manufacture these parts any longer and just out-sources them and puts them in GM boxes. But buying GM parts you are assured (hopefully) they meet the original GM specifications.

I happened to stop off at a local Chevy dealer yesterday and asked the parts guy for prices on the gasket and springs. I was shocked the prices he quoted:

3830711 Head gasket $34.16 each
3911068 Valve Spring $23.27 each

Sounds like he took the list price and doubled it! Obviously I did not place an order. I will try another Chevy dealer where I get realistic prices.

Rocco------


I guarantee you those are not GM list prices. Those are the DEALER'S list prices.

[Gary B.]

Re: 1967 Small Block Steel Shim Head Gaskets

Rocco,

GMpartsdirect.com lists the MSRP for GM # 3830711 as $14.69 and the MSRP for GM # 3911068 as $12.37. But their shipping and handling will add substantially to the costs.


Gary

[Duke W.]

Re: 1967 Small Block Steel Shim Head Gaskets

As I previously stated the ...711 head gasket is NOT what was installed at St. Louis, so why would you want to buy one for what would probably be a premium price.

Most engine rebuilders use thick composition gaskets since they will tolerate more warp than shim types even though most of these guys cut the heads and block wiping out the stamp pad date.

When rebuilding you may need to tailor the CR for available fuel octane, so different than OE pistons (OE equivalent SHP forged pistons are VERY expensive) and different than OE head gasket thickness will likely be required to attain the target CR. AFAIK NCRS does not measure head gasket thickness in Flight Judging, so you chose based on your target CR.

You don't need NOS parts inside engine since they can't be seen. What you need is OE equivalent parts. For decades Federal Mogul manufactured and sold OE equivalent parts - built to the GM prints - in the aftermarket. - mostly under their Sealed Power brand. GM was not interested in manufacturing low volume parts for decades old products. The F-M number for the ...068 valve springs is VS677. Up until a few years ago you could buy a set of 16 for about 25 bucks, and what GM sold were probably manufactured by F-M, but GM sold few because their price was much higher.

Unfortunately since F-M was bought by Tennaco a few years ago most the the F-M OE replacement parts supply has dried up. It appears they are no longer manufactured, but there may be inventory out there. You have to search.

Duke

[Rocco S.]

Re: 1967 Small Block Steel Shim Head Gaskets

Thanks for the additional information. I will look for the F-M VS677 springs Glad its not. on eBay and at swap meets. I was also concerned the the head gasket thickness was checked during NCRS flight judging. I would perfer to use thicker comosition head gaskets to lower compression a little. 11:1 makes it necessary to use an octain boost at fill ups. I can no longer get 94 octane. Most stations offer 93 however.

[Kenneth F.]

Re: 1967 Small Block Steel Shim Head Gaskets

In the mid 1960's I replaced the short block on a low mileage 1962, 340 H.P. car. The engine I removed had 2 steel head gaskets under each cylinder head.
I still have had one unused steel head gasket from those days. It measures .018 in the flat, and .047 where embossed.
Letters GM and a backward letter S above the GM are embossed on the gasket.

Ken

[Duke W.]

Re: 1967 Small Block Steel Shim Head Gaskets

Double gasketing at Flint on SHP/FI engines began in mid-'62 production due to customer detonation complaints and carried through to the end of '63 production. There is a TSB on the subject.

'64 SHP/FI engines returned to single head gaskets. The chamber relieving machining operation for the 2.02/1.60" valve set added a couple of cc to the chambers and the later closing inlet valve of the 30-30 cam bleed off more compression at low revs.

The advertised CR dropped from 11.25 to 11:1, but could be as low as about 10.5 if the block was decked with worn broach tools that could raise deck height by up to at least .015".

Duke