A833 4speed OD trans Swap Question

What size is your Universal joint at the tailshaft? If your output shaft on the trans has 26 splines, everything will fit. If it's 30/ large U-joint, you'll have to run a conversion joint or do something with the yoke or driveshaft.

If you do have a 26 spline output shaft, you could skip machining anything and simply swap parts in the transmissions.

Check this article that Dick Landy wrote up, when these transmissions were new-

http://www.forabodiesonly.com/mopar/showthread.php?t=202564&highlight=a833+overdrive

You have all of the parts you would need to swap the gears into a 23 spline input shaft/ 26 spline main shaft trans, if that is what you happen to be running in the car, currently.