SeattleSy#1255 said:
many scrap the 700 and go th350 or 400....
nothing but bad experience with 700's here, espically with high HP applications.
there are a few good vendors and peeps that can help.
I would not say many scrap the 700 and go 350 or 400. How many are there?
The 700 can survive if prepped properly and taken care of ie no hot lapping and being careful about how long you hold it against the brakes. There is no doubt the 400 will last longer at a higher power level for cheaper money.
However be careful to listen to Ed Hess as he has a very limited application for his truck. When he does drive it on the street he drives it like grandpa and slows traffic.

It works well for his application which is occasional street duty but mainly track use. If you drive it on the street and drive it on the interstate you will hate a 400. I regularly cruise at 70-90mph out on the interstate......try that with a 400. Much more fuel and wear and tear on the engine.
As to answer your real question with something other than "go 400"
A few I know of that know what a syty is are listed below in no particular order. Who you go with may depend on location price etc.
Roadmaster Trans. now known as Dr. Evil
John Waller
Mikle Lee @ RPM
George Blake
Phoenix Transmission in TX They have a great 2 year warranty.
Brian Hartman