I have two 90 burbs. My built rig is a 2500 with a 350cid and th400 trans. The "new" one is a 1500 with a 350cid and 700r4 trans. I need to swap the tcases and need to k lnow if they are interchangeable. Everything I have found says that the 700r4 has a 27 spine input shaft and the th400 is a 32 spline...except in 1990, when only one option was available. Does this info sound right? I know it's as simple as dropping both cases and counting splines, but I would hate to drop them both if the 700r4 case will not work.