5th Oct 2009, 16:49

Don't listen to the previous two comments, you drive your car and enjoy it. What is the point in keeping it stored away until 2000 - whenever when it MIGHT be worth a lot of money? And keep the original engine in it. If it craps out, then go with a 307 or Olds 350 if you want, but don't do a swap just because "everyone else's crapped out". But enjoy your car, if you truly waited this long to own one, why would you not want to? You only live once right?

28th Oct 2009, 11:27

I'm the original poster above. After a few minor body repairs, replacing the heater core (which was leaking coolant), putting in a new battery, and rebalancing the tires- I have to say I have a wonderful automobile. I'm pretty pleased with the performance of the V6 for daily driving, but if it needs a rebuild down the road I may opt for the 307 V8. Everything I read leads me to believe it would run smoother without much increase in gas consumption. Do the V6 and V8 use the same automatic transmission? I read online that the Cutlass downsized to a lighter duty transmission (200 series?) for these cars that can be overwhelmed by the torque of a more powerful engine. So far my transmission has been trouble free.

28th Oct 2009, 18:19

If you put in a 307 V8, also get rid of the TH-200 that's there already. It can actually barely handle the V6. Get the TH-350 for the V8.

29th Oct 2009, 12:30

Yeah the 'turbo 350' transmission is probably going to be the cheapest transmission you can find anywhere, and it fits the 307 perfectly. It's also very strong and durable.

8th Sep 2012, 13:35

The best drive train in these cars is a 305 5.0 liter engine and a 700R4 transmission.

The Canadian model came with the GM 305 instead of the Olds 307. The 307 is good too, but the 305 is bulletproof reliable.

The car came with a 200R4 transmission, but an upgrade to a 700R4 is highly recommended.

I have this drive train in my Cutlass, and it is flawless, super powerful, and reliable as all heck.

These are great cars, I love mine.

15th Jan 2015, 00:08

I have a 1985 Cutlass Supreme and it has the V6.

I'm having problems... when I put it in reverse, it takes about a second or two to actually start going. That's it though; other that that, it runs and drives well.

I would like to take it cross country. I like keeping stuff original if possible or rebuilt with warranty. I'm not looking for extra power; I like the amount of gas it uses now. I'm just looking for somebody that can maybe rebuild my engine and tranny. Any suggestions?

16th Jan 2015, 04:16

With the delay in the transmission, it needs to be rebuilt. As far as the 3.8 V6s, they are pretty strong runners. Instead of a full rebuild, update the oil pump and change the timing chain. As long as the compression is good, those two repairs are all you need. Those were the two weak points on that motor.

18th Jan 2015, 04:02

Good comments.

The timing chain can be tested for slack by a qualified mechanic. If you have to do it, the oil pump (which resides in the timing chain cover) can be replaced at that point. In terms of the oil pump itself, unless the oil light is coming on at idle, in gear, with a fully warm engine (30 minutes or more of driving), it is likely OK.

In terms of the transmission, the 3-speed 200c that was standard behind the 3.8 V-6 was actually pretty reliable at that point (the late-seventies, uh... well). You may (again) want to take it to a decent mechanic to see if it merely needs servicing, or more costly repairs.

Regardless, enjoy :)

19th Jan 2015, 03:14

G Body Cutlasses are already pretty collectible, and are only going to increase in value.

I used to have one with a 4 barrel 305; boy could that thing go.

The previous owner had replaced the 200R4 with a 700R4, which is a very good upgrade. The 700R4 is more heavy duty and was used in pickup trucks, GMC vans, etc...

I would suggest dropping a 305/700R4 combo in it if you can afford it, otherwise it may just need some tuning up, a few mods, etc...

19th Jan 2015, 15:00

The best, and easiest engine swap is to start with an Olds 307 (durable, but slow) and replace with an Olds 350 or 403, and back it up with a turbo 350 trans.