Which intake manifold

I am guessing the 4131 AFB would be under 500cfm. I have seen them go cheap at swap meets. I got lucky and bought a MP M-1. I had an Offy, and a Clifford with the humps for nitrous or EFI bungs. Sold them both in hard times. I know I have a iron super six intake out there in the shop. IIRC the Offy is a better street intake over the Clifford.