Norm, Have you even bother to check the valves clearances? When get to close to zero clearance they can get to where they will not start due to ramp decompression at the top of the stroke. Valves can stick open when this close to Zero clearance.
I don't see many L-side (Side Valve) engine any more but when I did I would get in engines that started one day and the next day would not due valve clearances.