intake gaskets (and should i block the heat crossover)

[diymirage]

so I bought a felpro gasket kit for my 75 360
it came with 2 sets of intake gaskets, one steel one fiber (or whatever that cardboard stuff is)

im using a weiand action plus aluminum intake
what gasket should I use?

and would it be a good idea to fab a little block off plate to close the heat crossovers going into the manifold (I was thinking 3 thou shimstock)
or is that best left alone?

 

[gliderider06]

Use the ones that have the larger ports. The steel ones are for the small ports. I cut a small piece of sheet metal to block the cross-over, but that is me.

 

[rumblefish360]

Block the heat cross over if the car doesn't see chilly weather. Otherwise, warm up times will be extended and drivability may suffer until the engine thoroughly warms up.

 

[diymirage]

I will drive it in the cold, not in the snow but I think I should be good

do I count on the gaskets to keep the block off plates in place or should I put a dab of RTV on there?

 

[EL5DEMON340]

I would use a little thicker that .003 something around .008 to.010. If your going to drive it it under 50 degrees more than just a few times I would still use the block off shims with a 5/16" hole on each shim. If your going to drive a lot under 50 and into freezing weather and using a choke just leave it open. I would RTV it in place.

 

[diymirage]

I like the idea of punching a little hole in there
I have whatever size shim stock needed at my disposal so I can do 8 or 12 thou just as easy as 3, the only reason my first thought was 3 was to keep gasket distortion to a minimum