You can leave the compressor off if you want. It has its own separate belt, it runs off of the crank using its own dedicated pulley (the innermost one). No other accesories are affected by it.
One thing: There are no 'big-block' Pontiacs.
They all use the same size block with the exception of 'short deck' 265/301 engines.
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My wife says I never listen to her, at least that's what I think she said.