Is there any one has some info on an intake manfold gasket from a 1961Corvette that is in the front and rear (rubber) of the intake. I was told by someone from a show that on the rubber gasket orginaly had a GM tab loacated somewhere visable. My question is where is the GM placed?

Thanks, Barbie

 

If you get a chance, fill in your profile. To answer the question, the tab was an integral part of the gasket, ie. molded into the gasket, about in the middle. Bill.

 

Those gaskets only fit one way, you can't get them wrong. Although, the recommendation around here is to skip those gaskets and use silicone gasket maker instead. The gaskets eventually ooze out from under the manifold and cause an oil leak, especially behind the distributor.

 

Barbie --- here's a pic of a big-block ('65-74) set of original GM gaskets for the intake manifold valley, front/rear ends. Small block might be similar. In the case of the big block, the gasket is the same for front and back, but the tab will be on the INSIDE of the manifold (can't remember which) on one of the ends, so the GM tab is not visible there.

 

Here's what the small-block tabs look like.

 

The reason they slip out is due to the use of silicone. If you use adhesive as recomended by Fel-pro. They stay put.
The fool proof way is to delete the end gaskets and use a high quality oil resistant silicone gasket maker. Such as permatex "right stuff" Use laquer thinner to make the surface oil free. Put a 1/4 inch high bead accross front and rear valley walls. If using Fel-pro,Use no silicones or sealers on the actual intake manifold gaskets. Not sure about other brands.

DO NOT LIFT MANIFOLD TO CHECK THE SEAL. Torque to specs and let sealer dry overnight. Then drive away.

 

I never had one of those rubber gaskets squeeze out and I use wheel bearing grease for gasket lube/sealant---everywhere, all intake gaskets, oil pan gaskets, water pump gaskets. never had a leak from it, the grease makes opening up the engine SOOOO much easier, as the gaskets will come off the surface easily, rather than having to scrape and scrape and scrap.

The grease is mostly a racers trick for motors that get torn down frequently, but I used it almost exclusively, until recently when some of the better silicone sealants came out, which also make cleaning sealing surfaces not too difficult, and still provide additional sealing above what the gasket does.

The only time I use silicone in stead of gaskets in on the manifold ends of motors where the block or heads have been decked, and attempted use of the end gaskets makes installing the manifold a problem due to clearance changes.

If you have gaskets squeezing out it sounds like a crankcase pressurization problem.

Sometime in the 1960's/1970's, GM went to drilled block webs for the nubbed gaskets. You can use tabbed gaskets on a drilled block, but not nubbed gaskets on an undrilled block