One can increase the CFM rating a little but NOT BY THE SIZE OF THE "Butterflys"(Throttle valves) in the base plate if we're talking Holley here. The size of the holes in the main body determine CFM rating of a Holley carb and any other as far as I know...No way to increase CFM rating other than removing the choke horn and assy., but this doesn't seem to be popular with this croud...Doing what your "Buddy" says would be like installing 2.25 In. and 1.880 Ex. valve in a set of heavily ported "915" heads and still running the stock exhaust manifolds. Kinda like taking a shower with your rain coat on, or Screen doors on a submarine...