My 2 cents would be run a set of Vortec heads (off of a late model truck) with the 700R4 and a medium rise intake and about a 600CFM Carb. The Vortec heads add 40Hp easy on a healthy bottom end with the better designed runners, ports, and chambers.
While you have the trans out, pull the case apart, lose the spacer that is with the clutch/discs, and replace with additional clutch/discs. This will prevent you from burning the clutches.
For drag racing, I have done both manual and auto. Auto is the way to go for consistency.
