I have what I thought was a 3800 SCII from a 1997 Regal. I got the harness and trans separately, although I suspect the harness came from the same car as the engine. The 4t65e HD came from a 2000 GTP. I was starting the wiring last night, and NOTHING matched up to the ECM plugs with the diagrams I have. I got some diagrams from att/subzero350, and now they are all mysteriously unavailable, gone. I have read many threads on here that says 'make it like the 1997 GTP'. I have considerable differences on where the wires are to go, how is that going to work? Do I just wire it up according to the diagrams, even though they aren't at all like they were removed from the ECM plug? Does anyone have the diagrams anymore? Confused....

EDIT: I did look at two other harnesses from 98 bonneville and the wire colors are the same as the diagrams I have for the 1997 Regal.

[This message has been edited by ferrarixxxman (edited 04-29-2008).]

If you are not positive on which car the harness came from I would go by the diagrams and there should be some differences between a 97 Regal and a 98 Bonneville as many things changed between 97 and 98 on the 3800 engines. Even the PCM's are completely different in shape and the emissions systems also changed in 98.
Either way you look at it the 3800SC from 97 to around 2000 fully interchange but the PCM's all do not so you have to wire the hnarness to match the PCM you are using to make it work. Dan

I have the wireing diagrams from an 03 Bonniville (send me a pm if needed).

do not do anything with 97 PCM's, I would just get it wired to a 98 GTP standard.