In looking at heads how much flow will a 502 at 5500 rpm require.
Is the monstrous flow of some of the new head needed. Don't want to buy more than i need. thanks in advance

All 502 engines come with rectangle port heads and they are overkill already. Most performance increases at 5500 come from installing a smaller intake port head. Go smaller not larger. 290 - 310 cc intake ports are closer to optimum than the 320 cc heads already on your engine.
Sincerely
Dennis Moore

Well there you have it, right from the mac daddy Truckin himself. Go with smaller ports for max power at that RPM.

I agree with Truckin! Those stock GM rectangle heads are too big as they come!