I just put a 89 S10 T5 in my Model A. Looks like it has an electric speedo on the tailshaft were a cable might also go. Is it difficult to change it to a cable speedo?
I had mine swapped out for an earlier tail housing that had the mech speedo drive. Hooked right up to the stock Model A cable.
You will need to get an earlier model tailshaft with mechanical speedo, the bullet hole is smaller and If I remember correctly, in a different location on the output shaft, you will also need the appropriate drive and driven gear to calibrate your speedo. I did it and if i had it to again I would go this route http://www.dragonaero.com/SpeedChangerMechanicalPage.htm
I did it, too. Swaped the tailshaft for a mechanical one. The drive and driven parts are tha same as TH350 parts. The drive gear will fit right on the mainshaft with the appropriate keeper that works for the TH350. Maybe I had to deepen the little dimple in the main shaft the keeper locates on? not sure. If you need more info search the kingofallT-5 threads. Frank.