I worked late today, and had to go to parenting/antinatal classes tonight. So no gearboxing. And tommorrow after work I might be making a 6 hour round trip to pick up the numbers matching A15 for my sunny. but when I get the chance, I'm going to finish pulling down the low kms four speed to compare parts. The hard part with the short 63's here is finding them. I think all ours came out of 710sss violets. I've heard A10 stanzas had them too, but they're very uncommon here. (I've only ever seen two, and one was a rally car that comes over from OZ to race a few times a year)
I'll report back with my findings after I finish disemboweling the (hopefully) donor box.

It's a real pity nissan didn't fit the 63a to all their a series powered cars. (And H165 diffs too!)