I'm building a 572 pump gas hemi now for a local customer for his 1970 Challenger street and show car, it has a Holley EFI system with dual 1100 CFM 4150 throttle bodies,Stage V heads, rockers and EFI manifold. It should make well over 700 HP (probably nearer 800+ HP)and a little(40Ft.LBS+)more torque than HP on Oregon 91 octane pump swill
I do make more HP per C.I. on my wedge stroker motor builds than I do with a hemi motor with similar C.I. and compression
On your deal I would shoot for 10.5 to 11 to 1 with aluminum heads and right or under 10.5 to 1 with iron heads
That C.I. with a 4 speed and street tires in a A body should be fun, especially at WOT