With a Recommended Top Rpm of 4200, a 302 is not going to need much for Carburation, a very small 4bbl, like a 390 cfm would be overkill
302 cu in at 4200 rpm can inhale 367 CFM, at 100% Volumetric Efficiency, However an engine from that Era, would at best have, 75% VE, so it would inhale 275 CFM.