Thread: 2004 cadillac engine fitting a 1997 seville sls

will a 2004 cadillac sts engine fit a 1997 seville sls

will it fit probly but to control motor you will need to change the comp. & wiring harness and possibly the trans

No they will not interchange. The blocks are different, not to mention the heads, 97's have plug wires, 2000 up have the coil packs. Intakes and harness are different. For you SLS motors from 1997-99 will only work. I work on these all the time, I do alot of motor swaps and headgaskets. I do all the drilling and timeserts on the blocks.

Well...I agree with jayodziana that blocks are different..