[JohnBoy]

I have a 1968 Chevelle SS with a 396 350 hp. The original intake manifold has a channel in front of the primary intake holes under the front of the carburetor. At each end of this channel are holes that go down. To where I am not sure. I don't know if this channel has exhaust going thru it to heat the carb or is it meant to have fuel and air running thru it into the engine. Should I use a gasket that covers this channel so the carb is not exposed to it, or should the gasket be cut out in this area?

 

[Dave427]

There is exhaust going through that channel. It is meant to warm up the carb yes. You need the correct carb base gasket or it will leak exhaust or if you use the wrong gasket the exhaust will burn out that gasket. What i did to customer's car to except a newer carburetor, I drilled and tapped the holes , to except pipe plugs to block off those holes which were not covered with that particular carb.

 

[Tom Mobley]

there's carb gaskets that have a channel for the exhaust crossover deal. trick is, you have to use a thin stainless steel shim between the gasket and carb. otherwise the exhaust eats the baseplate.

I've plugged a few of those holes in the manifolds. IIRC they're about the right size for 1/4 NPT. Seems like I had to tun the tap in real deep to get the plug to thread in flush or something.