I havent seen the bloke or the bike for a couple of years but there is a bloke down this way that built a A65 with a A10 crank. I dont know a lot of detail such as how he fitted the alternater, unless it was a super rare alternater A10 crank. Dont know what rods or pistons he used, anyway he ended up with about 750cc and easily the smoothest A65 I have ever ridden.
I have always thought A65's are one of the best designed british twins ever, unfortunately they vibrate that much they are almost unrideable.
Here is a pic of my 1970 Thunderbolt, I gave it to my son as an act of revenge !