SBC intake manifold gaskets

I want to run an old Nicson 3 X 2 manifold on a 290 H.P. Chevy crate motor. It looks like the ports are much smaller on the intake than on the heads. Is there a particular Fel-Pro gasket that works on these older intakes?

 

try the gaskets for a 55 chevy. But don't be surprised if there's a leak around the outside of the gasket, where it doesn't meet up with the much larger port on the head.

http://www.rockauto.com/catalog/x,carcode,1326406,parttype,5424

 

As far as gasket sealing is concerned you are better off with the manifold being smaller. If you have enough material you could grind the ports to match but I doubt the HP gains would be worth the trouble.

I would use the gasket set made for the older 283-327 engines and use a 1/4" bead of black RTV under the ends instead of the rubber seals.