What do you think is a reasonable hp est for a 305TPI with a Paxton S/C (5psi) accel injectors, Edlebrock headers and SLP cat-back.

Its 190hp stock (auto trans)----over 250?

I can ballpark the headers and exhaust but have no real clue how much 5 psi might add.

I always tend to think of the psi in terms of 14.7psi being the equivalent of doubling your cubic inches. If that holds true, then 5psi makes your stock 215hp 305 (rough guess with the exhaust) a 285hp stock 409...at peak.

I'm pulling those numbers outta my a$$ pretty much...but it's probably fairly close.