1987 chevy caprice. Classic brougham

Kinda depends on the heads, but 750 is pushing it. I'd stick around 600cfm.

O ok cool I have a 350 with aome double hump heads

Like Ken says you won't get an benefit from a 750 cfm carb without a hot cam and headers and maybe some head work.

O ok cool thanks

With a mostly stock engine with double hump heads select a carb that is from 550 to 650 cfm. A 750 is too big, but would work just fine on a big block.

K thanks

Why those my 91 caprice original cuts off if I creep turn meaning turning kinda slow like in a parking lot waiting on Mrs.Doubtfire to cross on by smh it’s such an embarrassment buts starts up as if nothing is wrong