carb size for 512 stroker?

if you have 1.5 rockers that's a .548 intake/exhaust cam

with 512c.i. i'd say 850HP holley, no choke. mech secondaires.
you dont need 900 950 1000 dominiators etc.

performer rpm intake would be better.

you definitely need big mama headers. not the little 1 5/8". your 2" should be fine

at 9.5:1 you will be perfectly fine on street gas. a bigger cam is a waste unless you can get the comp ratio to 11:1

if you are looking for et's then you are better off putting $$$ into chassis