FlatFenders

I have a good Olds 260 V8 that I have been told will bolt up to the bell housing and transmission on my Jeep that currently has a 225 Buick V6. In the past I have had a 231 Olds V6 in the Jeep and the 225 was an easy swap when I could not find another 231.
#1 - is this true?
#2 - the Olds 260 is from an automatic transmission so I would need a manual flywheel. Any chance the flywheel from the 225 V6 will work. If not what would you suggest?

joe_padavano

First, all BOP (Buick, Olds Pontiac) motors from 1964-up use the same bellhousing bolt pattern, so yes it will bolt up. That's the only thing that does. EVERYTHING else is different - motor mounts, flywheel, etc.

Second, every 225/231 V6 GM ever made is a Buick-sourced motor, even if it came out of an Olds.

Third, most Oldmobile motors that came from the factory with an automatic trans do not have the crank drilled for a pilot bearing. Installing a manual trans requires either having the crank machined (preferred) or using an adapter bushing that requires mods to the trans input shaft.

Fourth, the 260 is at best a doorstop. It weighs more than the 231 and barely produces more HP. GM build far more Buick V6 motors than Olds 260s, so I'm amazed if you can't find one.

FlatFenders

I only thought about using the "260 doorstop" because I have one from a Cutlass my son totaled 15 years ago. As for the 231's, I have not found any in my area (north central Illinois) for years. Scrap yards around here don't keep much of anything anymore that is more then 9 years old. The "cash for clunkers" government fiasco in 2009 probably took care of most of them. I have seen V6's in G.M. cars (rear wheel drive) that have the distributor on the back of the motor, unlike the Buick version. What are those? I have heard people call them "Chevy 231's" and they say they have the Chevy bell housing pattern so I avoided them. One major advantage of the Buick V6 is the distributor on the front when used in a ****** Jeep conversion.

joe_padavano

Those are Chevy 229 motors, not 231s (though both round to 3.8 liters). Essentially 3/4 of an SBC.

joe_padavano

Given how many 231s GM made, I'm surprised you can't find one. Another option to consider is the later Buick 3800 Series II/III motors. These were mainly used in FWD applications, but GM also used them in the fourth gen Camaro/Firebird. While the Series II/III motors share basic architecture with the earlier 231s, the block and head castings are different and the port spacing is different, so pretty much nothing interchanges. They also use the narrow "60 degree metric" bellhousing bolt pattern found on the 2.8 liter V6 motors (yes, I know the Buford is a 90 deg motor). You can use an MT bellhousing from either an F-body or S-10 truck with the 2.8 or 3800 motor.

Of course, the Series II/III motors are all EFI and distributorless ignition, but many people have transplanted them into earlier cars. In particular, you can get the 3800SC motor with the supercharger and 260 HP.

Sugar Bear

Can you find an early Buick V-8 to install? Have never done it but it may be worth exploring. Was thinking that the flywheel may bolt up from the V-6.
I agree that the 260 is quite low on power and a little heavy.