I suggest 83-93 S10 for the T5. The shifter location is further forward, and is directly vertical - not skewed to one side as with the F-body (trans installs cocked to one side).
14-spline is most common. I think the trick is to use the S10 (2.5L or 2.8L) disc with the 250ci 11" pressure plate. Somebody will know for sure.
