dont let anyone tell you your 71's too big and too heavy.
first off how much money do you have to throw at this rice frying machine? That is the first step, develop a budget.
Lots you can do without aluminum heads although that would be real nice.
I say go to a 5 speed AUTOMATIC and a 4.30:1 posi setup for your 9" rear. Get a Hiolley 600 and an edelbrock 4bbl intake for your 2v heads and you will burn down most anything in your way.
The
trans will be a 4R70W from a 98-2001 v6 mustang(350-500$ junkyard) Complete 4.30 third member (1200$)
Computer form Baumann engineering(becontrols.com) 250 intake 350 carb, duals with H pipe 450 - and finally a helmet to soften the blow of your brain smacking the back of your skull.