How much hp should my chevy have?

350 bored .30 over, Comp cam (high energy) duration .50, Lift.477/.480, flat top pistons, all Msd wiring and distributor. E3 spark plugs, Edelbrock shorty headers, Weiand excellarator intake, Edelbrock 650 carb. the heads are 462624's, please dont tell me they're crap heads because i already know this, they are however 2.02/ 1.60's which are even more crack prone lol. Im also gona put some 400 Small block heads on the motor in a month. How much more would I get with the 400 heads then the 624's?