Correct Intake Mainfold Gasket

[William C.]

Re: Correct Intake Mainfold Gasket

I believe that is correct Patrick, as there is a corresponding difference in the intake port size on the gaskets, at least the examples I have. I'm going to try to post some pictures later today for better understanding.

[William C.]

Re: Correct Intake Mainfold Gasket

Here are a couple of pictures showing rectangular and thumbnail tabs as well as one with a scale to reference port size differences.

[Bob J.]

Re: Correct Intake Mainfold Gasket

Here are a couple of pictures showing rectangular and thumbnail tabs as well as one with a scale to reference port size differences.

Hi Bill,
my 65 parts book lists the 3734115 as fitting all 63-65 Corvettes except FI.
I believe thats wrong since a 340, 350 and 365HP all use the big port heads(fuelie).
But I think these 3734115 gaskets do fit all the small heads (250HP) in the 63-65 years . Bob

[William C.]

Re: Correct Intake Mainfold Gasket

I'd agree that the small port 283 and 327/250 likely used the 3734115, with the 300-and up engines using the larger gasket. That is also a logical explanation for the square vs round hump, easy for an inspector to catch an incorrect gasket. Also the parts books I have don't show the second design gasket set until 1968 applications (3931600). Any thoughts? I don't have a '66 or 67 issue parts book, just early '65 and May '68.

[Ronald L.]

Re: Correct Intake Mainfold Gasket

I did the study a couple of years ago and its' somewhere on this hard drive, ... from memory, the 68 started the nibs that plugged into the great wall of china as some call it - just as the 66 and up 427's do. Those tabs with the logo are rounded and very small as the 427 and are next to impossible to see on an assembled engine.

54 -67 had very visible tabs front a rear with some variation in that at one time this multi cavity tool had more than 30 cavities. Think about it, a 5 minute cycle time and these seals went on every 327 283 engine Chevrolet made, they could make the engines faster.

[John D.]

Re: Correct Intake Mainfold Gasket

Great photos Clupper & Jorjorian. Also one of the better posts here for me.
To repeat what some of you said. The repro gaskets are not repros at all but Fel-pros that have been recut. The 60 down style with the square tops started off life with a rounded camel hump.
The verticle rib is a piece of cake to remove., If you have a good vise put it in a vise. If not a ball peen hammer or hammer period will remove the verticle rib from the repros.
The repro gaskets are quite nice except for the end rubbers. Also very affordable. But if you want the real deal for your show car and are chasing the points there is nothing like a NOS set with correct rubber tabs with nice GM logo. I never really new the scoop on the GM logos though as I see them with a small font, see them with a large font and don't have a clue. For my 63 show car I picked out the ones with the large font on the tabs so guys like Clupper could see them.
Once again thanks for the excellent post Don Harris. You did well buying those repros for less than 30 bucks though. Just remove the verticle rib and run with them. As far as are the real deal end tabs readily available the answer is no. Being that it cost a ton to have stuff reproduced in rubber I doubt if anyone is going to reproduce them as you would never break even. Most of the guys throw those rubber end seals away anyhow as they are very prone to leak. JD

[Bob J.]

Re: Correct Intake Mainfold Gasket

Great photos Clupper & Jorjorian. Also one of the better posts here for me.
To repeat what some of you said. The repro gaskets are not repros at all but Fel-pros that have been recut. The 60 down style with the square tops started off life with a rounded camel hump.
The verticle rib is a piece of cake to remove., If you have a good vise put it in a vise. If not a ball peen hammer or hammer period will remove the verticle rib from the repros.
The repro gaskets are quite nice except for the end rubbers. Also very affordable. But if you want the real deal for your show car and are chasing the points there is nothing like a NOS set with correct rubber tabs with nice GM logo. I never really new the scoop on the GM logos though as I see them with a small font, see them with a large font and don't have a clue. For my 63 show car I picked out the ones with the large font on the tabs so guys like Clupper could see them.
Once again thanks for the excellent post Don Harris. You did well buying those repros for less than 30 bucks though. Just remove the verticle rib and run with them. As far as are the real deal end tabs readily available the answer is no. Being that it cost a ton to have stuff reproduced in rubber I doubt if anyone is going to reproduce them as you would never break even. Most of the guys throw those rubber end seals away anyhow as they are very prone to leak. JD

John,
maybe its just my bad eyesight but those reworked early gaskets look like somebody punched the area next to the tab with a hole punch.
On the NOS pic I posted it is flat on both sides of the tab, not rounded.
Bob

[William C.]

Re: Correct Intake Mainfold Gasket

I agree that you and that is the same conclusion that I reached, one of many issues with relying on parts manuals for restoration guidance.

[Kenn S.]

Re: Correct Intake Mainfold Gasket

I tried looking up "Gary P in Florida" and had no luck. Must be a newbie thing on my part.

I have been searching for the correct set for a '70 LS-5. How would I locate Gary so I could call him? He's not in the "Members List," or not that I saw. ???

Thanks!