If it really pumped 220 and has a 509 then it has 11:1 or more, and a healthy short block. If thats the case I wouldn't go with a smaller cam!

The converter and intake will hold you back, but that thing should still rip. If it doesn't i'd start looking at the carb and spark curve.

Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street