My guess would be they did the timing job themselves and didn't get the crank bolt tight enough when reassembling? Bolt loosened up and started wobbling, took out the key and the pulley? Somehow didn't wreck the crank.
Gotta sell off the fleet of stick shift's as the wife is having another knee replacement surgery.... it makes me sad but I did pick up a '49 international truck to rebuild.
Haha! I like the wife alright... she puts up with what some would call "crazy" plans. I'm building a full tube chassis and using the cab, hood, grill etc. It will be LS powered with an auto trans, 4x4 with either dana 60 of fabricated 9" axles
Yep, common symptom of the crank bolt coming loose. Crank itself is much harder than the key, so it doesn't surprise me that the crank isn't damaged. BUT, it frequently jumps time in the process. My comment was fairly sarcastic. But in seriousness, I'd do a compression test before buying.