Trevor:
Good advice. I've been gradually acquiring parts for a MK 3 motor. (Shipping has cost more than the parts themselves) I have crankcase with cams (serviceable, but could probably use some work, hence the question), oil pump, crankshaft (thanks to you), two sets of Japanese pistons( Honda CB750 and Suzuki GSX 650), barrels, heads (with a broken intake outer valve spring), two magnetos, and most of the timing case gears, timing chest cover, and assorted bits of the flywheel and clutch. It's a spare motor so I don't mind mucking about with it, including gas flowing the heads, upping the compression, etc.
I'm not in a big rush, so am just picking up bits and refurbishing them as time permits.
We're in the middle of a snow storm here. It's not too cold (-2 degrees) but we're in the middle of getting about 20 cm of snow, then perhaps some rain tomorrow. Perfect for pottering indoors.
Best regards,