4 Barrel on a stock slant

Correct, Edel does have a 500 CFM AVS. Carter didn't. It had only two sizes in AVS, 625 & 750. 625 was used on 340 & 383, 750 on the 440.

Of interest when talking about flow ratings & cu in, Pontiac had a Hi Perf 230 cu in inline 6 in 1967 that had a 750 cfm 4bbl Quadrajet carb. Engine made 215 hp, not far off 1 hp per cu in.