I got screwed back in 1990 by a guy who did a SBC for me. Dumb ass didn't tighten down a rod nut properly, and it came off during a pass. Found the nut, with threads perfect, down in the pan.
Of course, since it was a 'race' motor, he exempted himself from any liability. Thankfully, his old ass is now pushing up daisies.
Never let anyone else touch any motors of mine from then on out.