My 440 died yesterday, and I would like to avoid throwing parts at it

treblig wrote: "What made you decide to remove the timing cover???"

It died suddenly while driving, and would not re-start. Spark was good, as was fuel delivery. Backfired through the carb when cranking, and there was a lot of lost motion in the distributor shaft when rotating the crankshaft back and forth. It was the latter which convinced me it was the timing set.
Oh OK, it's just that there were so many suggestions on how to approach the problem I was wondering which approach you decided to use. treblig