nicolas1187

Hi all,I am looking to start working on my 78 cutlass supreme brougham. The engine is a 260 and the transmission is a turbo 350. It started with my grandpa brand new and was passed on to my father. In the early 2000s the engine failed he had the engine rebuilt and It ran until about 2008, at which point it stopped running and sat until 2020, then it was handed to me. Due to the time it has sat and the fact the motor has been bored once, I was told that a rebuild would not be advisable. Does that sound right and if so i am looking for suggestions as what motors I could drop in the quickest to get the car running again. Any help would be greatly appreciated!

old80cs

Any 260-403 Olds V8 will be a direct drop into your car. I replaced my 260 with a 350 Olds years ago and it was very easy.

Greg Rogers

Welcome!! Just because the engine quit doesn't mean it neesd a complete rebuild. There is a huge # of items that will make a car quit and not restart- check it out first. The 260 was a good but gutlass engine.

BlueCalais79

I agree with the comment that once it's been bored out once, to avoid boring it out again. Mine's been bored out .30 over and once that cycle is run I will be looking for a 350 R motor to replace it. If you are ok with 105 hp, the 260 is for you.

Also, be glad you have the 350 trans, that's a good start for a larger bore engine if you go that route.

Sugar Bear

X2 on above advice...

Don't bore it twice,

Find out why it doesn't run and do a compression test,

260's lacked oomph but we're economical and VERY reliable. They didn't have enough power to hurt themselves.

Had one in a '79 used it tow a small boat, had 200K and ran well. If it's going to be a driver don't be in a rush to 86 the 260.

Good luck!!!

olds 307 and 403

It could also be a TH250, which is still better than a TH200 but weaker than the TH350, look for a stud by the cooler lines. I killed a TH250C the first time behind a 403. Either an Olds 307, 350 or 403 is a direct swap. For a cruiser, don't over look a good running 307. It is a 35 to 45 HP and 40 to 50 ft/lbs of torque gain over your 260. Add dual exhaust, even 2.5" dual pipe will fit under the passenger side hump and gain another 20 HP and torque.

nicolas1187

​​​​​​​forgive my ignorance, but is there a difference between the Olds 350 and a GM350. I know Oldsmobile was a division of GM. I've been checking out crate motors and gm seem to always show up. My master plan is to get "Blue Thunder" (my families name for it) back up in top shape and give it back to my dad.

Sugar Bear

Yes most "GM" is short for Chevy. It's a lot different and would require many mods including probably the transmission.

GM said keep your call all GM...I say keep your Olds ALL Olds !

nicolas1187

When it was running it wasn't running great and had become a money pit and my dad needed a more reliable car which is why it got put aside. Due to that and the fact I wouldn't mind putting a little more power into it. I figured upgrading is the best option.

nicolas1187

any recommendations on where to look for Olds motors

rocketraider

Your profile shows you're in Texas near San Antonio. South Texas Olds Club is based there. Go on the Oldsmobile Club of America website www.oldsmobileclub.org and search under Chapters for their contact info. There are four OCA Chapters in TX and someone in those groups might have a good small block Olds engine laying around or help you get your weenie 260 going.

I have a good 74 Olds 350 in a 78 Custom Cruiser but the car comes with it and would have to be transported from Virginia!☺️ 'Course you'd get a leaky Turbo 350 as part of the package...

260 has the same bottom end as a 350, and doesn't make enough power to hurt itself so they tend to last a long time. But since it's already got a .030 overbore probably better to replace it if you can't get it running well.

Sugar Bear

I'd still do a compression test and find out why it doesn't run, it may be in excellent condition and drivable until you find an engine.

A 65-67 330 CID or a 350 CID 68-80 would be good. If you're going for performance a 68-76 350 block is stronger than a 77-80 350. 403 would be a pretty strong runner in almost stock form.

Good luck!!!