Hi, I was looking all over the forum for my question but was unable to find the answer, maybe I wasnt looking right! Anyways, I have a 1990 eldorado and I am looking to change the engine. I have found a 4.5 engine from a 1990 deville and was wondering if it will fit my eldorado, i think it should because it is the same engine, but will it bolt on correctly? I was also considering the 4.9 engine, but I know I need to change the transmission and possibly the ECU, will it be complicated to do? or should I just stay with the 4.5? Thank you for your help.

The 1990 4.5 from the Deville and Eldorado are identical.

I don't know the answer on what it would take to put in a 4.9 in your car. I believe the transmissions from 1990 on up are the same. Both engines are Port Fuel Injection. Hope someone can answer your question.

Are you from lincoln/omaha. If you are come buy my engine off of craigs list :]