replace 96 cutlass engine & trane w/91 Lumina

Here is a some background info. 96 Cutlass first had overheating issues changed out the whole cooling system, pump, radiator, temp sensor, thermostat (3) etc. Still hot. Then the tranee began to go. won't accelerate correctly. 1st & 2nd slow rise with high rpm. I believe that the 1 & 2 shift solnoid was bad the entire time and was the cause of the overheating. I have acquired a 91 Lumina and want to attempt to pull the engine & trans and put into the 96 cutlass. Here is my question. What issues/complications, if any, might arise when doing the change? Your knowledge will be greatly appreciated.

Welcome to AF. Not a direct swap, subframe, axles, wiring harness and pcm are just some major differences, I wouldn't do this you are going backwards.

the newer 3.1s are better any ways.(95 and newer). They have more hp and torque. I would fine a newer motor if i were you. It will be a lot easyer.

Thank you for your comments.