Help with intake heat crossover?

I am doing a whole top end swap on my 1980 lt camaro when i run into a problem. My brother says if i want more performance out of my small block chevy then i should block the heat crossover in the bottom of the intake manifold. The manifold is an Edelbrock Performer, not the RPM model, and I dont have enough cash to spend on another intake. How would i close up the crossover on both sides without messing up the sealing properties of the intake?:banghead: Please help me.

Removing as much heat as possible from incoming air does increase performance by means of introducing cooler denser air. However in this instance I really think the gains are nearly negligable. Already switching from the cast iron intake to the performer is enough of a gain in it's self.

im wanting to get a performer intake....just curious what are the gains i'd be looking at? ( dont mean to hijack)

Same thing, better heat dissipation, a huge weight loss, better air flow characterisitcs just to name a few. A performer is a decent cheap upgrade.