It is many years so I had forgotten that the PJ and UJ use different output shafts (one retained by a bolt the other by circlip).

However I think you'll find the splines are common as I have seen a rod change box with rubber unis - they just sort of float about.. but do work...

When I decided my S UJs were getting too tired I asked my local BMC expert for advice. His response was that I should find the newest rod box I could get my hands on and steal the appropriate parts. They're still these 20+years and 100K miles later.... I think there might have been some new balls at one point but can't be sure.

Cheers, Ian

The change point for the Pot joints was not the introduction of the rod-change box.
The first rod change boxes used rubber cross joints.
The out-put shafts are very different. I can not imagine that it would be possible to fit a pot joint to the earlier type even if the spline was the same.

You're right, they're quite different but still interchangeable. Both yoke sections just slide up and down the splines but not enough to actually fall off. The end of the drive shaft/output shaft sort of bump up against the rubber crosspiece and this stops things sliding too far.

I only drove the car about 20 feet (onto the trailer) but dodgy joints were the least of this car's problems...

BTW Bill's advice re the newest box I could find was not directed at getting any particular "version" but just having bits with the least wear...

Cheers, Ian