I would give that 2.9tranny about 2 or 3 good launches, and its case or mainshaft will give out ( more then likely the case ) .
If your gonnan use an auto, a C4 is cheap, common, and has a plethora of aftermarket parts. C6's are rare and do NOT have a removable bell housing. FInding a 6 bolt SBF C6 is VERY hard and VERY expensive as most were used in larger trucks and Broncos.
For a Manual, the old school T5 is VERY common, boneyards are full of them. The prefered Trannies in Mannuals would be a World Class T5 ( thats what I presently have ) , Tremmec 3550 or a Liberty 5 speed ( what I'm moving to this spring ) .
A 302's strong point.. short stroke and like its older brother the 289, it can tac-up REAL quick and get into a lot of torque really fast. The 80's 302's only had 225HP ( just 20 more then a 4.0 ranger engine ) but they had 300_lb/ft of torque to go with it.