I have a similar story. I was driving a 80 Diplomat and somehow the slant six grenaded the #1 connecting rod straight out of the block. It made a hole big enough to put a fist through. It ran terribly but made it fifteen or so miles back to the house.
2 years later, I am still curious about how this happened. I never ran it hard and kept the fluids changed regularly. I am guessing that the old woman that had the car never changed the oil in it EVER and it sludged up the bottom end; thus starving the bearings??