67 corvette 427ci/435hp

[Mike Hambrick]

Hi I would like to know what is the correct gasket for the gas tank lid for a 67 corvette 427ci/435hp big block. Is it a paper gasket or is it a rubber gasket to pass ncrs judging.

Thanks
Mike

[John S.]

Re: 67 corvette 427ci/435hp

Mike,

If you a referring to the fuel cap, it uses a thick paper gasket; not rubber.

[Joe L.]

Re: 67 corvette 427ci/435hp

John and Mike-----

Yes, a thick, cellulosic (i.e paper), medium brown color gasket. Beginning in 1969, the gasket changed to neoprene or nitrile rubber and the cap with this gasket became SERVICE for all 63-68.

[Jim T.]

Re: 67 corvette 427ci/435hp

My original owner 68's original vented gas cap and my original owner 70's original non-vented gas cap has the same type of gasket made of the neoprene or nitrile rubber.

[Joe L.]

Re: 67 corvette 427ci/435hp

Jim-----

I thought that 1968 used the same cap as 64-67. Very early might have. However, upon further research I find that most, if not all, 1968's used cap GM #3921689. This was a 1968-only piece. So, now I know that this cap used a rubber gasket. I wonder how it differed from the 1969 cap, GM #3952708? Can you post a photo of it top and bottom?

[Jim T.]

Re: 67 corvette 427ci/435hp

Joe, I do not have a digital camera yet, mayby someday I will be able to post pictures when things like this come up. I did just take a quick examination of my 68's cap and my 70's cap. The only difference I can see between the two is that my 68's cap says VENTED on top above the twist handle and has a vent hole on the underside of the cap. My 70's cap has SEALED on top of the cap above the twist handle and no hole on the underside. They both have the spring assisted sealing function when twisted on the filler neck and have identical fluting around the circumferance.

[Joe L.]

Re: 67 corvette 427ci/435hp

Jim-----

The 1970 cap is not the same as earlier. As you've found, it's a sealed-type cap. The reason for this is that, for 1970, all Corvette fuel tanks had the integral pressure-vacuum valve and no longer required a vented cap.

The 1969 cap was a VENTED cap (even though late 1969's had tanks with an integral pressure-vacuum valve, too). Inasmuch as I now know that the 68 cap had a rubber gasket, I just cannot figure out what the difference was between the 68 and 69 caps. It may have been some sort of difference in the pressure and vacuum release points.