At a crossroads, SB guys please chime in.

MidTexCuda said
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?

Well, a lot depends what n the head being used. A race block, if found, because there not being made any more and there drying up fast, or more accurately, they are dried up, may possibly only be found in a 48* taller angle instead of the production 59*. While the 48* angle is better for racing, the cost of a cam core is ALOT! And then you have to send it Out to be ground.
The weight savings between the block family is about 100lbs. But you could make the power up easy with a big block.
Stoking a 400 to 500 is easy. Taking a standard block beyond 440 cubes is hard.