What year is the donor, and the recipient?

 

I was wondering if it is possible to take a newer say 2000 5.9 and mount it to a older 36rh transmission out of a 1983 ram?

 

Sure, it'll bolt right up. The older trans won't have the cutout for the crank sensor though, so, if you wanna use the fuel injection, you will have to cut that out. If you switch the engine to carb, and basic electronic ignition, it becomes a non-issue. Gotta use the right flexplate though. 5.9 is externally balanced.