Hi John. Thanks for the offer of assistance....I certainly think I'm gonna need it. After your comment about the Head part number, I went back to the parts list that I have, and you're probably right. I was looking at 67-0965 which is for a complete head. The number I have matches what you suggested, so all good there. All the valve gear part numbers match the SF list, and are all new. So far I have replaced the following with new parts - Valve gear, push rods, cam and cam followers, pistons and 1 x con rod, mains and big ends, (got crank ground to .020 under. New piston set (.040 over) and cylinders bored, SRM oil pump (because why not???), new timing side bush, all the others look ok. New engine breather oil pressure relief valve and the little spring and ball inside the timing case. All new nuts, bolts, washers and studs throughout.
When I bought the motor on EBAY, he reckoned it was only missing 1 valve.....yeh right. What I've done/bought here is just to replace what really wasn't there.
So, once I get all this together, then I'll worry about such exciting things like electronic ignition, converting an old 2nd hand dynamo to 12v, and look at using a 376/80 carby that I picked up along the way as well. Have got a fairly decent gearbox with 6 spring clutch set-up that I will refurbish with new parts. It only has the duplex primary drive, but I'm ok with that. Not getting too carried away with "must be original". The original idea was to build a bobber, but if I can keep the over-all appearance similar to original, then that will just be a bonus. Regards