I am a 78 years old hot rodder, living in Washington state, USA. I just completed building a T Bucket, actually a '26 roadster, using a '63 Olds 215ci aluminum engine, sister to the Buick 215, and the fore runner to the Rover V8. In '61 - '63, Olds used a 3 speed automatic often referred to as the 'mini slim Jim', and it was pretty much a piece of junk, with terrible shift habits. The Buick used a 2 speed automatic, called a 'Dual Path', which is not a bad trans, very small in size, but weak. (Both of those trans were only built from '61 to '63, and are getting hard to come by here.) I chose the Dual Path for my T bucket, because of it's tiny size. (On a T Bucket, you need all the foot room you can get!) The bad news is that my junk yard supplied Dual Path trans has burned out clutches for reverse. A rebuild kit for this trans is about $400 US$. Finding someone with experience and knowledge on this trans that can actually perform the rebuild is near impossible.
As an aside: I like the Olds head design better than the Buick design, as they tend to breath a bit better, and the valve covers are set at an angle similar to a Chevy, which to me looks better. It's pretty much a wash though, either Olds or Buick and pretty much the same, with almost total parts interchange, and many parts interchange with the Rover version. For example, I'm running Rover exhaust manifolds since mine were cracked, and a Rover starter, because it in geared and allows me to run a small garden tractor battery in the car. PS, The car just squirts as it is so light, with my tubing home built frame and thin glass body!
All that trans talk is the bad news, the good news is that since this engine is the same bell housing pattern as the Rover V8, any automatic that bolts up to a Rover should also work on the Olds. AND, there is more good news, I happen to have in stock an '85 Jag XJ6 trans that is freshly rebuilt, it is a BW65. I understand that some SD1 Rovers used the BW65, so I'm thinking that I could use this trans, if only I had the parts to mate it up to the engine. I'd for sure need a bell housing, perhaps a flax plate, spacer(?), torque converter, etc. as well. I'm here looking for information on this setup, as all my internet searches have come up dry. IE, what years SD1 used the BW65/66? Did any other Rovers use that trans? Etc.
I know there are many extremely knowledgeable dudes on this site, so I welcome information from all. I also have a bevy of other cars and rods, so I may have some knowledge and can contribute in other areas on this forum.