I have used the Bowtie Overdrive transmissions in several vehicles and I've had very good luck with them. For a heavy car the 700 works real well. The low first gear gets it rolling. I'm building a 427ci LSX that we figure will put out about 550hp. Bowtie built me a Stage 3 200 4R that should handle that. It's going into a light car - '32 Ford hiboy sedan. The gear spacing in the 200 4R is similar to a close ratio 4 speed, except of course it has overdrive.