I don't have a 351W but the setup would be very similar. Without digging out all my paperwork, you'll need the motor plate adapter between the engine and transmission, and there's a thin adapter (~1.5" thick) between the transmission and the t-case. Look up the input spline count for the t-case - I think it's 27 spline. Driver's side drop. I went with the 3.8 low range case. For a lot of what I do, I like the 2.7 reduction in the planetaries. 3.8 for the slow stuff and stupid low (10.xx) for exhibition purposes only.
Todd Z.