Thread: 1997 Olds Cutlass Supreme 3800 swap

Ok...some of you guys may know, I daily drive a Jeep...and it isn't exactly the greatest on fuel (even though I average 21.7 MPG around here.) Well, the Jeep is going to be turned into a lifted offroad machine, my Isuzu Rodeo is going to take on winter duties, my GP is strictly a toy, and I will be in need of a daily driver.

So, I'm walking around the junkyard, checking out all the potential vehicles, and I stumble across a very nice 1997 Cutlass Supreme coupe. I'm not a coupe guy...but this car is CLEAN. Gold with tan (ewww) interior, but absolutely mint other than a bump in the hood which can be easily fixed. So, I ask the junk guy why it's there...typical smoked 3100.

So, here's where my gears get turning. The CS came with the extremely terrible 3100 mated to a 4T60e. The 1997 GP GT came with a 3800 mated to a 4T60e. I have 2 complete 1997 GP GT drivetrains with harness and PCM just waiting to go into something and there's this gorgeous CS looking all sad. What kind of project is it going to be to wire the 3800 into this car? I'm not looking at the car, so I don't know how the wiring routes and can't find a decent picture online. If it's something that I can accomplish in a leisurely weekend build, then I'm going to buy it. Plans down the road if it'll work? 1.9 rockers (no cam because can't rev the 4T60e above 6k due to pump design), ported heads, and everybody's favorite...a snail set to wastegate pressure (thanks to Greg Badass for leaving me his GP to drive around.)

So, any thoughts on what kind of project this would be? Looking for helpful advice. Don't go all blah, blah, blah on the mods or some other bullsh*t. Just let me know about the engine wiring or constructive thoughts.

I can MAKE it work...basically I'm after "this will/will not plug right in."

I'll figure out something...if all else, I have the tools to repin the connectors and can always splice new where needed I guess. I know the 1997 CS uses the same PCM as the 1997 GP GT so I could go through and look it all over in the wiring diagrams. Just wanted the power distribution center on the P/S strut tower to be there awaiting the same connectors from the 3800 harness. LOL

Getting ready to run out the door. Perhaps later this evening.

I can almost garentee that it will not "plug in". Blah. BLah. Not saying that it is impossible, but after being part of a project that involved a 3800 going into a 1994 Grand Am GT, and tons of research on 3800's going into Fieros, I can tell you, it will be quite the project.

Well, upon further research, most of the wiring from the 3100 harness pins out exactly the same as the 3800 harness from the 97 GP GT. So, what doesn't pin out the same, would be rectified: some wires added, some removed. Obviously, it would take a little time, but since most of it is the same, it won't be near as bad as I originally thought. As far as the 98-99 Monte Carlo harness, I don't have access to one of those vehicles, and it would be hit or miss if it had the 4T60 trans as it was offered with both depending on options. PCM plugs in...most of the wiring would plug in...I think I'm going to give it a go. Now I just need to talk to my junk guy.