between replacable and non-replaceable u-joints...which is the best choice?

I think there is no choice -- the tailshaft either has one or the other.

Replaceable is better, as you can just change them when they wear out. With non-replaceable, the tailshaft has to be rebuilt. Well, sometimes. Some cars that have "non-replaceable" joints can actually be replaced by the do-it-yourself.

1200s have replaceable u-joints:

i got a tailshaft made for my h165 (rather than trying to find a ute one) and the guy that did it was showing me that the front uni-joint is quite small and not replacable, he said this is a weak link for high power engines, he machined out the mounts for the u-joint and put a larger replacable u-joint in and also the rear he put a replacable in so i can change the uni joints at home when required (quite easy really)

Hey PW, the H165 is the bigger differential in newer B120s.

There's been some controversy about this, but apparently 1971-1973 1200s (B110s) have replaceable u-joints.

While were on the subject of uni joints, ive converted my auto to manual, ive but in the clutch, clutch pedal & gearbox and am in the process of making a new crossmember. my problem is the tailshaft i have for my manual wont fit the diff, it seems the joints are bigger in the autos. how can i fix this problem.

hmmm im thinking only way that could be is if the diff was a borg warner from a 120y, does the diff centre come out the front or back of the diff housing

ive done conversion with no probs