Did you find TDC by the piston method or valves. If you get TDC you could put new marks on the damper. You probable will just have to time it by trial & error. It,s very doughtful the rebuilder got the cam off. It would barely run if that was the case. Jaspers puts out some good stuff. The occasional miss is probably from carbon on the plugs. To adjust the idle mixture, with the engine at an idle slowly turn the idle jet in till the engine slows down. Then back it out enough to smooth it out, usually about 1/2 turn.
