Currently, I have a 205 from behind a TH350, with no adapter, and a 203 and TH400 setup that is complete. I have a 70 Longhorn 4x4, I'm building a NASTY (around 700HP) Rat for, it will be between 527 and 535 cubic inches. It has an HO 72 rearend, and I'll use my Dana 70 or get a Dana 60 for the front. I'll use the truck to play, pull, and drive. Should I use what I have and build a 203/205 doubler (3 stick) or should I get something like an Atlas? I'm keeping the 400, it'll have a 10" ATI converter, and is built to take 1000HP.