well, I want to eventually go 460 (block)/4-speed.
What I neglected to mention was that this would be temporary, and involve a complete rebuild, some minor porting & polishing, plus the engine has an edelbrock carb & intake and full accel ignition (I know a lot of people say accel is crap, but its better than stock '83 GT parts). This would be assuming the car has high milage and craps out on the compression test.
As for the tranny, again to do with the possible milage, and if it'll most likely end up manual tranny anyway...
The '83 definatly would move, if it ever hooked up. It'll smoke the rears right off the car if you want it to. It usually spins both if you dump it, its got 225/60-15's on newer "turbine" wheels (I want the wheels, not for the '70, but I'm one of the few who like 'em). It's pretty quick, open header, makes the ground shake (very literally).
It'll almost definatly be a while before I've got the green for a built big block & 4-speed, plus the 9" out back, so this is my "just in case." Like, if the engine & tranny aren't hangin in. Of course a 351W/C4 combo... hmm, that describes a few million rusty 70's pickups...