Hi everyone. I'm joining here to ask the experts some questions.

I have a 75 Olds Cutlass Supreme. It'* my only car and it averages around 11.9/16 city hwy mpg, which hasn't been very fun with gas prices. It also has started to rust in lots of places. I'm hoping to do some engines mods to get better mpg and horsepower.

In the meantime I'll be looking for a good 3800 series I or II car, so I'm here to hear from real owners of those cars and their mpg, as opposed to numbers on fuel economy.gov and OEM ratings, which seem to be pretty inaccurate, and ignore lots of variations among models.

Right now I found a set of 72 cylinder heads at the junkyard and I am rebuilding them so that they will be reliable before I put them in. They should raise compression and horsepower and give me a impressive boost in mpg.

Welcome to the forum. I'm not too familiar with the Series 1'*. But, the question is, what do you really want to do with this 3800 in the future? If your looking for a decent car that gets decent fuel mileage and have no plans to mod it, any car with a 3800 II from 95 and up will be fine.

Are you looking to do some mods to it? Even some "mild" mods require tuning. Then your going to be needing something 1997 or newer. HpTuners is the only one that supports 1997 and newer cars with 3800'*. EFI Live does not. The list of mods for the Series 2 FAR out weighs the Series 1 engines.

Welcome! Got any pictures of the Cutlass? My girlfriend has a 76 in her back yard waiting to be restored

welcome to the site, my 98 sse has the na 3800/ with 3.05 fd ratio. helps with local/rural mileage. its got k+n drop in and e3'*, 175k miles and ive changed the oil every 5k since i got it about 10yrs ago. she gets 28 usually rural two lane, im sure it would get higher on the highway but we rarely take it on the hwy.

Welcome to the site. Start up a thread on your problem and I'm sure we will get you all set.

Welcome looking forward to pictures!

Hi Mike, thanks for the welcome. I'd like to find a 97+ LSS but if I find a nice, low mileage, garaged creampuff for the right price, I'm not going to turn my nose up at anything older. I'd probably go as old as '88.

I really just want a nice daily driver that is reliable, which I'm sure 170 hp in the SI or 200hp in SII would be more then adequate. If I did any modding, it would be more along the lines of trying to get max mpg. Horsepower isn't a big deal to me, but mpg is. I've noticed the 3800 seems to get just about as good mpg as many smaller engines (3400, 3100) although this is probably highway. Once I get something and know what I have, I'm definitely interested in tuning it to be the most efficient and sharing anything I learn along the way.

I'll have to read up about HPtuners. I've read some about the DHP pwrtuner system.

I'll have to find some older ones, it currently has some big rust issues. I'll post some pics soon. What trim is your Gf'* 76? (Salon, Supreme, *) and does it have the fastback or notchback? Mine is red with notchback and full white vinyl roof (causing the rust issues) Let me know if you have any pics! There'* another forum for just 73-77 Oldsmobiles, you might want to let her know!

Thanks jw. Those SSE'* are beautiful cars and I'd love to find a nicer one for sale. Thanks for the mpg info. I'm researching which cars had which drive ratios but the info seems tricky to find.

Thanks Dan. Nice Bonne!I started another thread with some horribly specific questions about the 3800s- hopefully questioning where no form question has gone before. I'm excited to see what I learn.

I'll post some soon. Nice Cutlass convertible. I remember sitting in one as a teen at EPCOT outside of the closed (and now-demolished) GM World of Motion pavilion. It was a a year before they were going to start building the Test Track ride.

the best mileage i heard of with a 3800 is 32-34 from my father inlaws 96 bonnie se, thats mostly highway. all other conditions being equal the 3400 and 3100'* will get 3-5 mpg more. ive had quite a few as i drive alot and usually get wbody coupes for my dd. i got several 38mpg tanks from my 03 monte 3.4. i always get 28-30 local mileage as well

welcome to the site

Welcome to the forum