piston id.

[townsends20]

I am having a sort out of all the old a10 parts i have laying around, i have a set of used pistons, these are the original 9.1 from my rgs can you tell me if thay are standard, the underside carsting numbers 67/1371  the top side what i can read is 67-1555 bsa v30576h?? there is no scoring two rings missing and only one pin. so with new rings and new pins there  good. ( feel free to make an offer if its up your street)

[bsa-bill]

http://www.hawkshawmotorcycles.com/bsa3.html

According to this it seems  +20 that's assuming different part No for different oversize, my barrels are +40 otherwise I would have been interested