Hey, I haven;t posted in a while cus I got rid of the project.
I was short on time and money and everything else in between, so i got rid of it.
But if you have any questions on setups just ask. I still lurh around on this board and in time.... There will be a bigger badder luv project in the works....
I would suggest a th350 or th400 I would lean more toward the th400, stronger, I would mate it to a np205, prolly the easiest/cheapest route, and aside from being a bit on the heavy side. it is very strong. make sure to do some research on tailshaft splines etc. you can ALMOST find a style of np203 or np205 or np208 that will bolt up to a th350, th400 or 700r4.
I personally have a 350 TBI to a 700r4, back to a np203/np205 doubler that is driver's drop to a HP Dana 44.

I am almost ready to test this setup out...
I was running the 700r4 to a np207 then to a np231, both worked great and had low gearing.
Aaron