Have you checked the insulator on the distributor where the coil wire goes to the points? My H was giving me fits, would run good most of the time, sometimes would not fire at all. Chased the problem for quite a while & finally found a crack in the bakelite insulator on the distributor body, where the wire is bolted to the points (wire connected on outside of body, points on bolt on inside). Replaced the insulator with a plastic one from a Datsun distributor (I think that's what it was, you know about the CRS problem that us older guys suffer from on things that happened a couple of years ago) that the parts house found would fit and WHALLA - haven't had a problem since. Just a suggestion. (My $0.02 worth. jal-SD)