I was wondering if I could use a 1983 - 1985 Ford Mustang intake manifold on my 302 truck, but without the EGR vlave?

There is a hole cut out of the carburetor mounting pad on the stock 1983 - 1985 intake manifold for the EGR.

Will a 4-hole carburetor spacer effectively seal off this hole? Or am I going to have to use a different intake manifold that didn't use an EGR?

 

Usually the carb spacer will not cover that hole. If you can get a piece of fairly heavy stainless steel sheet metal and fabricate a piece that covers it, you can then use the manifold to spacer and spacer to carb gaskets. Try not to use aluminum, the exhaust gases will rot it through, plain steel would be better. Sounds like a nice setup.

 

Are you looking to eliminate your EGR?

 

Lots of people plug the heads or plug the manifold itself. If it's steel, you could probably weld it shut.

The custom spacer plate solution is also a good (and non-permanent) one, but you will probably want to replicate the outside dimensions of the EGR plate so that you can use an EGR-to-manifold gasket.

 

You probably don't want to block the exhaust crossover unless you are strickly building a race vehicle. No heat = poor cold weather running. Yes, Shark racer is correct, I didn't state that, but it does need to match the outside dimensions, the gasket is usually a good pattern.