Brady,
I personally have researched this and have found that if your truck came with the Turbo 400, the 700R4 would be the best option primarily because the dimensions are closer..please verify this.
BUT, if your truck came with the Turbo 350, then I strongly recommend the 200R4..it is a virtual bolt in, and you can utilize the original driveshaft.
Final note..I personally prefer the 200R4 and Turbo 350 over the other two because these transmissions have less internal rotating mass, thereby avoiding sacrificing HP as well as rev-ability. They are still quite strong for even the wildest street machines, and proven by numerous racers.
It is only for the extreme high torque applications and excessive hard use that I would recommend the T400 and 700R4.
