I have been following this post, I would suggest you inspect the ignition points, sounds like there might not be enough clearence when the cam is on the high side to open them. Should be .015-.017 clearance when on the open (high) cam. If you don't have enough clearnce at the points the coil doesn't get enough time to load for the next shot. You can also test this with a dwell-meter. Go from neg side of coil to ground with the meter, should read 28-31 degrees. Good luck, Buford 8.