I think you just need to swap the 1000 output shaft to the 1100 motor. Requires pulling back covers. A couple guys and I have done it with 1200's. It will almost bolt up cleanly then. You will have to modify the frame a bit for the elec ignition unit. Other than that, it's a bolt and go. It's not worth the hassle of swapping trannies for the little gain of the 83. A taller rear tire would help some.