ok so i'm fiddling with a '62 a65 star.
does an a7/10 top yoke fit on it?
No they are different shapes.
can you expand on that
See this early A65 top yoke on ebay.
https://www.ebay.co.uk/itm/134953667294?itmmeta=01J0R3Z0KD3KTYCNCDXA4XV8SM&hash=item1f6bdd8ade:g:xEQAAOSw9ltkc3R8&itmprp=enc%3AAQAJAAAAwORpqS9%2BIHPcm0h0UI0h4H4cJ7%2BoSb9
And below photo is from a swinging arm A10.
i think youre missing the point of the question
i already know about the a65 ones and the a10 ones but do the holes line up? thats obvious
the '66 a65 top yoke isnt a dropped one and looks very similar to the a10 yoke
theyre all 6 3/4" (??) and the stem is the same diameter as far as i'm aware. its just the offset of the stem hole to the fork holes.
all it would take is a couple of lumps of billet and a lathe(or a cnc) and the difference due to the a65 drop can be sorted.