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Like said above most of your after market performance manifolds are blocked any way so it would be of no advantage to go through the work to chip it out and risk getting carbon spread through the engine.



Not so! My holley SD, Eddie LD340, LD4B, Offy etc have exhaust crossovers. Your Crosswind, Airgap etc. don't. We are talking about a truck here, not a racecar.

I run with mine blocked off on my 360. It is an aluminum intake. It is OK even down to 2* But that is aluminum! Not iron! Gonna drive in the winter up there in Idaho, and Northern Nevada with an iron intake? Do the job right.