Harry - thanks for the reply.
I set the points with a feeler gauge 0.018", as the engine wouldn't start (set screw on points had loosened, so points had closed).
Cam and chain alignment marks are set correctly with crankshaft timing mark spot on. But spark occurs 30 degrees advanced. You can't rotate the distributor enough to correct that 30 degrees - it'll hit the bearing underneath (see picture).
How would you recommend I move the timing back to TDC?
Thanks.
Tom