big block 8.2l 500ci problem

here goes i have a 1957 ford f100 you all know the ugly one year truck i have a cadillac 500ci 8.2l engine installed in it with a 650 cfm carb from brock and it is to small ,not getting everything i want out of the engine has anyone ever played around with this engine and if so what size carb is going to work the best for me i want to push this big block any help would be great thanks everyone

 

The stock Qjets on these were 800cfm. I have always ran a minimum of a 750 on my stockish ones. 800-850 CFM is what these big Cads like. On any of my 500+ inch Cads with Cam and head work I have run 850-900 cfm.