Leave the cubes for the guys that have heavy vehicles. Stick with normal cubes and let the heads and cam make you your horsepower! A larger motor displacement will ONLY move your horsepower peak to a lower RPM with all things equal. So my vote is an LS6 block (the windage holes are excellent), some large heads, the FAST intake or LS6 and a cam with a single pattern grind. With that and tuning, and a 6 speed trans you'd have a perfect 3000-3500lb vehicle power plant. Or you could just go RMT and call it a day

but I like beating up on people on all motor... it's like pooring salt into the wound. Oh, and then I tell em it's still 2 barrel TBI but that's beside the point. Don't do the displacement upgrade just for horsepower because that's now how it works.
__________________
, Jon
Owner of a Red Sled.
If it\'s EFI I can tune it. Specialize in 82-95 GM (yes Lt1\'s)
\"If you can leave black marks on a straight from the time you exit a corner till the time you brake for the next turn.......Then, you have enough horsepower\" - Mark Donohue