AMC Gearbox changes 1961 1962

Why do I see different part numbers for the rebuild kits for Norton gear boxes between 61 and 62?
Outer covers, kickstart, some bushings have new part numbers for 62 onwards,
I am rebuilding a 61, but neglected to ID the gearbox, I just overhauled it with new bearings and bushings inside like I have done on commandos, now looking at replacing the kick start bushings I see different #s in the book.
Also isn't this about the time norton moved out of the original Bracebridge st location?
Please educate this kid,
Thanks in advance to this great group of knowledge!

The parts book for 1962 says there are 2 different outer covers - one for 1961 and another for 1962.
It mentions the 1962 number is from NA1001 onwards.
The kickstarter bush is listed as different numbers for 1961 and 1962, and other parts too.
Looks like the whole kickstart area was changed - but not much else.

Nortons were still in Birmingham for 1961 and 1962, so that doesn't sound like it comes into it.
Interested to hear what you find out.

I believe the differences were to accommodate a stronger kickstart spring the end of which on the earlier boxes located in a drilled hole in the inner cover,not over a dowel like the later ones.The kick start shaft was also longer.

Ah ha, that's solved a couple of queries for me too.....good info....