I wasn't saying your engine couldn't make 2000 hp, I just think it's funny that you think a spool will make a difference in how a 2000 hp car acts on the street.
For your application, I think a well built Dana 60 or 9" Ford will do the job. I personally wouldn't mess w/ the 70, but that's just my .
A spool should be mandatory in my opinion. A GOOD powerglide would be my choice as well.

CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax