T400 with TH350 Tail Shaft

Not an expert on TH transmissions, but I doubt it.
Is this strictly a racing truck? Most folks today prefer something newer for less engine wear and better gas mileage.

For what you're planning to do with the truck sounds like a 4L60E if using EFI or 700R4 if carbed would make most sense. Easily built for 300HP and will bolt in with stock mounts and driveshaft. Should be able to find a local builder who can put one together for you for around $1500. He'll need all the specifics as to what engine, etc you're using.