Standard Cam is 67-334 on an early plunger, usually found on engines with the dished low compression pistons. 67-356 is sportier cam, a little more lively, originally found on the A7 Star Twin and then on the A10 S/A higher compression variants. Those flat topped pistons will be OK with that cam. Piston 67-572, standard bore, with oversizes 67-574 and 67-576 are all listed as 8.1. As usual the one you want appears nowhere, but 8.1 would be a reasonable guess, bearing in mind 6.5, 7.25, 9.1 were all options, but obviously with a flat top, 9.1 doesn't figure.
Interestingly the 67-356 Cam and 8.1 Pistons 67-572 were fitted to the Super Flash.
When you come to re assembly, it is a lot easier to assemble the crank, cases and gearbox as a unit, fit this to the frame and then build the rest of the motor into the frame.
Swarfy.
