negativeMatt Posted June 11, 2019 Report Share Posted June 11, 2019 If a guy was looking to swap a later 3.8SC into say, a 1990 GP, what would be the year range to look for in an engine/trans, parts car combo? (Asking for a friend) [emoji38] Sent from my SM-G935F using Tapatalk Quote Link to comment Share on other sites More sharing options...
Bake82 Posted June 12, 2019 Report Share Posted June 12, 2019 (edited) Here's the info: Any 97-07 engine and trans combo will work. It's slightly easier 98-02. Here's what you need from the GTP donor car Motor transmission PCM Rad motor mounts axles Here is what you need from a 98-99 monte carlo Z34/Lumina LTZ as it originally came with a 3.8 and the wiring harness is very similar to the 90 GP. Engine wiring harness (C100 at firewall will need slight re-wiring to work in the 90 GP and add the BBV wiring(I think)) rad hoses tensioner, and heater hose fitters(they are at a right angle vs straight on the newer ones, but the newer ones can work). heater hoses power steering lines PCM mount/case Exhaust downpipe AC components, everything from firewall forward axles 97 is odd because of the transmission and vacuum hose routing. 03 is odd because of the transmission wiring. If you use a 03 transmission, you MUST use a 03 PCM. 04-07 has a GEN V supercharger, you'll need a throttle body adapter to use either an L67 TB or Northstar TB and LQ4 MAF. Whatever TB you use, you'll need to match the TB Adapter. Additionally if you use a 04-07 transmission, you MUST use the 03 transmission. Axles: If using monte carlo transmission, they should bolt in not issues. if using GTP transmission, take the inner tulips that plug into the transmission, and swap the rest of the 1st gen axle into those tulips. They will pop in with no issues, assuming the original 1st gen trans was a 4spd. If 3 spd, it won't work. If I had to do this again, I would find the 98/99 monte carlo z34/lumina LTZ and steal all of the parts from. I would then top swap the 3.8 and run it in the GP. Good luck with your swap! Edited June 12, 2019 by Bake82 negativeMatt 1 Quote Link to comment Share on other sites More sharing options...
negativeMatt Posted June 12, 2019 Author Report Share Posted June 12, 2019 Here's the info: Any 97-07 engine and trans combo will work. It's slightly easier 98-02. Here's what you need from the GTP donor car Motor transmission PCM Rad motor mounts Here is what you need from a 98-99 monte carlo Z34/Lumina LTZ as it originally came with a 3.8 and the wiring harness is very similar to the 90 GP. Engine wiring harness (C100 at firewall will need slight re-wiring to work in the 90 GP and add the BBV wiring(I think)) rad hoses tensioner, and heater hose fitters(they are at a right angle vs straight on the newer ones, but the newer ones can work). heater hoses power steering lines PCM mount/case Exhaust downpipe AC components, everything from firewall forward 97 is odd because of the transmission and vacuum hose routing. 03 is odd because of the transmission wiring. If you use a 03 transmission, you MUST use a 03 PCM. 04-07 has a GEN V supercharger, you'll need a throttle body adapter to use either an L67 TB or Northstar TB and LQ4 MAF. Whatever TB you use, you'll need to match the TB Adapter. Additionally if you use a 04-07 transmission, you MUST use the 03 transmission. If I had to do this again, I would find the 98/99 monte carlo z34/lumina LTZ and steal all of the parts from. I would then top swap the 3.8 and run it in the GP. Good luck with your swap!You sir, are a legend! Sent from my SM-G935F using Tapatalk Quote Link to comment Share on other sites More sharing options...
Bake82 Posted June 12, 2019 Report Share Posted June 12, 2019 Just now, negativeMatt said: You sir, are a legend! Sent from my SM-G935F using Tapatalk Thanks! Added axle info as I forgot that Quote Link to comment Share on other sites More sharing options...
Amanita Posted June 12, 2019 Report Share Posted June 12, 2019 Does the Regal GS have a lot of incompatible parts with the Grand Prix or does everybody just say to get the parts from a GTP because that guarantees a supercharged 3800? Quote Link to comment Share on other sites More sharing options...
Bake82 Posted June 13, 2019 Report Share Posted June 13, 2019 (edited) 17 hours ago, Amanita said: Does the Regal GS have a lot of incompatible parts with the Grand Prix or does everybody just say to get the parts from a GTP because that guarantees a supercharged 3800? I think a regal GS/monte carlo/imapala SS will work as well because it's a w-body, and has the proper mounts. any other car with an L67 (H-body) have different mounts and therefore will work, but you will need to obtain the w-body mounts. Additionally I'm not sure if the PCM from the regal, mote, or impala will work(possibly BCM issues?). The PCM info may be wrong, but I thought it's something I've seen. In my swap I've used a variety of PCM, 00,01,03 GTP's, so I know they work! Edited June 13, 2019 by Bake82 Amanita 1 Quote Link to comment Share on other sites More sharing options...
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