With 4.10 gears, proper drag wheels, a diet and well setup suspension I say you can hit low 12's (High 11's with cams). If you're auto you'll definitely need a torque converter with a higher stall.
With a similar setup,no cams, I ran 12.46 but on factory heavy rims, stick car, and roadrace suspension. I went S/C so I gave up my quest for a low 12 sec N/A car.
Look around the internet for posts by blazing saddles. George is the real deal. He's down to 12.17 i believe N/A auto.
I would put those mods at around a 12.7.
I had those mods minus the charge motions plus JBA Longtubes (last minute install) and ran 12.691 on the last day of 05. I never tried that combo again since I added gears before returning to the track.