At the speeds Al is running and I'm sure wants to go even faster...I'd think if he isn't stepping into the blown hemi game, then he's going to go w/ a GM based powerplant. At least w/ those 2 platforms you can get any parts you need.

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