As for the ignition, I did check the gap when I had the cap off to remove the side cover. I did look at the distributor as a possibility because I was sent a video of the engine running(valve pieces clattering inside) before it was trailered down. It showed the distributor snapping back and forth as the manifold went between vacuum and pressure each time that cylinder went into compression. But nothing was found.
Nothing else has changed. It was driving along fine. The driver thought he heard a clicking sound but before he could focus on it, everything went to he**.
Did a compression test (5-130+, 1-0) lifted the valve cover and saw the valve parts. Tied the valve stem up out of the way (didn't know it had broken up)and pulled the spark plug wire. Started it again. Should have run like an engine with a miss, but wouldn't idle, sounded rough and like the timing was retarded.
R&R the head and put everything back.
The mods are pretty mild "old school", just letting it breath better. Fenton headers and Offenhauser manifolds have been around since the 50's. Everything was left stock. Point is, everything was working fine until ..........
There are only so many things that can cause the vacuum to drop (and remain steady) and I must be missing one.
