I have three transmissions to choose from, a TH 400, TH 350, and a 700R4 out of an 84 Caprice. The transmission will be going behind a 454 putting out about 450 horse power and over 500lb/ft of torque. The car is a 77 Nova weighing 3700 lb(guess), 3.08 rear end. I am leaning towards the 700R4 because I will be driving it on the highway and I like the overdrive. The car will also see the drag strip on occasion. Will the 700R4 withstand that kind of power? How expensive is it to build any of these transmissions to handle that power?