At a crossroads, SB guys please chime in.

thanks rumble thats what i wanted to know.
I was wondering because a stock 400 block will only take so much hp. Would something like a r3 take more?
Both BB and SB heads seam to flow close until you get to 4.5 bore BB stuff and then your into another block any way. Plus the cubes are close at 450 something to 500 and change.
Didnt know if SB would weigh enough less or cost the same. either one would only need to make 700 hp off boost and be able to do 14 to 20lbs on boost.
So in short which block would fair better (r3 ect. or stock 400- both done right) , how close would heads be, and would it save enough weight?