Carburetor size Question

I had used a 500 cfm on a 318 cop car motor with 360 heads and a mp 340 cam in the mid 90's, only thing i did to it was change the cam and that thing was alot of fun. So I then went to a 625- carter- made it more fun. Then I went to hell with it and put a 750 manual choke afb- that carb made a big difference right out of the box. So it depends on what you want to do. i know they say too much carb blah blah blah, but i have found some engines like a larger carb when it should not call for it. And i have found engines that perform better with a smaller carb. Based on what you have i would try a 750 avs/ afb or a Holley equivalent.