Opinions please

A
If you have auto trans 600cfm with vacuum secondaries , hooked up . FYI , the factory 4bbl had small primaries and secondaries for good throttle response . One step up is a 625cfm which will give you a little more . I wouldn't go any larger than 650 . A 650 will likely bog from a stop . Bigger isn't better .
Automatic transmission I have
I’ll look into a 625cfm as well
Thank you