I am getting ready to install a new Edelbrock Performer 750 CFM (electric choke) carburetor on my 1985 K30 Dually with a 454. Since I am using the stock cast iron intake manifold, with a spread-bore bolt pattern for a Q-jet, I am using a spread bore-to-square bore adapter plate, in order to install the Edelbrock Performer carburetor, which has a square-bore bolt pattern. My question is that when I test fitted the adapter plate to the carburetor, the adapter plate plenum partially blocks both the primary and secondary carburetor venturie pathways. I was thinking of getting my die grinder out, and grind back the adapter plenum area to match the carburetor venturie pathways better. Has anybody done this modification before, and have any advice on it, or would it be a waste of time because this engine is only a stock engine anyway?