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I just got a 1984 Cutlass Supreme V6 3.8. The engine is bad, I was wondering what bigger engine can I fit without doing to much modifications. Appreciate the info in advance.
Last edited by Litos88; July 2nd, 2023 at 08:21 AM.
If you find another G-body Cutlass in the salvage yard you should be able to take the engine out of it and put it in your Cutlass. The Oldsmobile 307 is the most likely candidate.
These cars could have the 3.8 V6, Chevrolet 305 V8 or Olds 307 V8, meaning about any SBC or small block Olds would easily fit. If you choose the Chevrolet or Olds V8, you need to get the motor mount frame perches and ALL of the belt-driven components' brackets from the donor engine. It'll save a lot of aggravation and time searching for the stuff later.
You could possibly look into a 4.1 (252ci) Buick V6 but that might not be easy to find. Also the Chevy 4.3 V6 should bolt up to Chevy frame perches but I'm not 100% on that.
And then there's the LS swap, but I purposely don't know anything about that.
Might as well figure on going through the transmission too if you go the V8 route.
Last edited by rocketraider; June 21st, 2023 at 09:59 AM.
If you find another G-body Cutlass in the salvage yard you should be able to take the engine out of it and put it in your Cutlass. The Oldsmobile 307 is the most likely candidate.
Thanks currently searching for the Engine. Appreciate the info.
Thanks for the tip guys. Question is this V6 slow?. From what I was researching it seems they have very low HP. Do you guys have any experience this V6. Also where do you guys buy motors online if any sell?
The motor mount frame pads are unique to the Buick motor. You will need to swap to the correct frame pads for whatever other GM motor you plan to use. Only Buick motors bolt to the current mounts.
Your trans is a TH200C. It's marginal behind the V6. Anything with more power probably wants an appropriate trans.
The frame on the G-body cars is not symmetric, so depending on the trans you pick, you may need a different crossmember. The TH200 crossmember also works for the TH350 and most GM manual transmissions. The 200-4R crossmember also works for the TH400.
If you plan to install an Olds motor (and any small block Olds motor is an easy bolt-in with the correct frame mounts), the 260, 307, 330, 350, and 403 are all externally identical.
Any different motor will require matching accessory brackets, starter, and exhaust. Buick and Chevy starters mount on the passenger side, Pontiac and Olds on the driver side. Wiring and battery location change as a result.
If you do plan to install an Olds motor, these are the frame pads you need. Note that they are RH/LH. Anchor 2328 motor mounts are the correct mounts for these pads.
The GM 3.8l is the most dependable engine GM ever built. I'm actually surprised if your's suffered bottom end damage. There were many different versions. You can check your VIN.
I actually know of someone who has recently spun a bearing in a Slant Six. I would not have thought it possible to kill one. The car was a factory slant six Challenger.
Yes a Buick 350 would be the easiest way to go and provide the biggest bang for the buck. A 68-70 motor with a four barrel would provide all sorts of umph. Your next step would be to change the rear gears..
June 21st, 2023, 07:14 AM
