Customer towed his '78 (or '79) Ford Fairmont wagon into my father's shop. The 302ci V8 suddenly died on the road and wouldn't re-start.
After confirming the no-start condition, I got to removing the distributor cap and observed the rotor while cranking the engine. No rotation. I pulled the distributor and part of the broken drive shaft came with it.
After removing the oil pan, it was filled with sludged oil. The oil was so thick, the pick up screen had clogged and was sucked inwards toward the oil pump; oil was still allowed to "flow" as the suction tube remained open. I suppose this was a fail-safe design?
I found the cause for the twisted/broken pump drive shaft. There was a small, broken off piece of hard carbon-like material caught in the oil pump gears, essentially freezing the pump, twisting the pump drive shaft breaking it.
New pump and drive shaft, cleaned out the mess as best I could and re-assembled/re-timed.
Luckily, the engine ran without knocking.
Questions were asked - found out that the owner used the "If full is good, over-fulled is better" logic.