My best was taking an Oldsmobile diesel engine out of a low mileage 1987 Buick Regal. That car was mint other then the engine. At the time the diesel engine was nothing more then a modified gas motor. The previous owner had bought it new, was tired of it cracking block and sold it to me dirt cheap.
The motor was a 350 Chevy motor bored fifty over with a set of Corvette 2.02 heads (double hump) with a three angle valve job. Mild cam, windage tray, double roller cam chain and a few other little mods. It also had a transmission with a Fairbank’s shift kit.
Changing the motor mounts was a real bitch. There were brake lines that ran through a hole in the frame. I wound up having to Elmer’s glue the nuts to a open ended wrench so I could reach the bolts and so I could put the nuts back on the new bolts for the motor mounts.
Also since a diesel engine doesn’t produce a vacuum, the brakes are run off a pump sort of like a steering pump. I had to change the brake booster, master cylinder and brake pedal.
I had two inch wide short headers on there so the exhaust place was able to tuck in the exhaust real tight and use a late model Camaro-like muffler. From outside the car you couldn’t see any of the exhaust and it sounded real nice.
Good thing I’m an electrical guru, the electrical system need some serious modification. I used an after market cap mounted HEI coil and that worked out OK. With the exception of the bottom of the wiper arms hitting it but that was an easy fix. I found out the hard way one day when it rained and the wipers stopped midway on the windshield. It made the coil turn too, I thought something had fried when the wipers stopped and the motor killed.
All said and done it lined up and looked perfect. Lined up perfectly with the existing radiator and fan shroud, which was nice due to the three core radiator that comes with the diesel motor. The extra heat control helped since it was bored fifty over.
The tall diesel gears in the rear end were a nagging problem. It didn’t run worth a crap in the ¼ mile but on the top end it ran like a NASCAR. It was very fast and stable on the top end because of the tow package the previous owner had installed on it from the factory. Front and rear stabilizer bars and heavy duty suspension because of the heavy ass diesel motor put in it. The car sat up about two inches in the front after taking the heavy diesel out and putting a lighter gas engine in it.
The dual battery set up was nice too since I was deep into stereos at the time.
There’s probably a whole mess of mods that I’m forgetting about. It was a mind twisting bitch of a job to do.
Would I do it again? You bet, but now that I ‘m married with a child, I no longer have the extra money to play with.
. Only real gearheads knew something was up when they heard me start it- the Mopar starter whine on a GM??? 
hahaha.
