Hey Super250:
Welcome to the "brotherhood of inliners".
If you do a search for "supercharged 250 chev" thread starting on 5/16/08, i think a lot of your questions will be answered.
I think in another thread, i read that lump ports would not be greatly beneficial in a forced induction engine. I haven't had mine on a dyno, but i think MBHD's guess about the horsepower would be pretty close.
If you still got questions, this forum's where to get them answered: these guys been there, done that! on any inliner question or problem.
Good luck with your project, keep us posted with photos.
Pappy
