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Swapping motors

in my 84 caddy is a motor which caddy should had left alone,that being a 4100…i want to swap this motor with another one that has more horsepower…what size motor could replace this sorry 4100…

The HT4100 is a real piece of work. Your best bet is to try to find a GM nut who has done engine swaps in these cars. If it were my car, I would figure out a way to make a Chevy 350 fit in there. The Olds 307 was also used in this car if I remember correctly, so that is another option, but I like the Chevy motors better. Maybe find the same model in a junkyard that had the 305 or 307 in it and take the motor mounts. They should work with the Chevy motor. The transmission should work. Little more should need to be changed, other than probably the exhaust and other odds and ends like fuel lines and necessary wiring. For someone who’s done this kind of thing, it will be pretty easy. For someone who hasn’t, it will seem like a daunting task. I highly recommend finding someone who has done something like this before to help you out. Having a shop do this will be extremely expensive, so that is probably not an option.

Go find a 3-4 year old CTS and take it around the block.You will soon drop any plans to re-power what ever relic you are trying to breath new life into…

Your '84 has a crude computer control system that makes engine swaps an endless frustration…1981 to 1989 is the lost decade…The worst cars ever made were made during this time frame…

Sell it and buy something you like better, the engine management systems were terrible as were the mileage and power.

Whitch Caddy is this ? there our 2 different 4100 V8’s and 1 V6 whitch is a good engaine 1 v8 is transverse mounted and the other is north south like in the Eldo or Seville FWD or the RWD cars the Olds 307 can by dropped in the the RWD and The Eldo & Seville but not in the fwd Deville and fwd Fleetwood.