You could save a lot of headaches if you bought the datsun 1000 drag car that was advertised recently which already included a 8.15 mustand shortened diff and was setup for a big block chev which will take a ca18, fj20 (a-la-jeff watson victor bray killer sprite), turbo rotor or sr20 turbo or whatever you want and has all the roll cage and the rest.
all you need is engine and box and the car is under a grand with shaiteloads of time and money thrown at it only to not be able to afford a special race 2 speed powerglide. Apparantely the box going to cost about another 4-5 grand!!!. Engineering from scratch is for those in the trade, rich people of drug dealing panel beaters.