A ran a combo about like this in a 70 Camaro,The cam I ran was mech. roller cam the specs. where 245/255 at .050,lift was .630 on the intake and .650 on the exhaust it was cut on 112 lobe seperation.I would try a RPM Perfomer Air Gap manifold.I started with a 750 Holley but ended up witha 850 Demon carb.This combo. seemed to work well with 175 shot of N20.