My dad finally discovered a problem in his '55 Chevy where a main oil bore was plugged with a broken drill!
It'd broken off and was just left in the block. No doubt the next 250 blocks on the line after that one were simply missing a hole!
BTW, my dad fixed the problem by cutting the cheap Chevy drill out with a VERY EXPENSIVE state of the art super tungsten carbide tipped drill bit ~ and a hand drill.
I doubt it ever occurred to Chevy's QC managers to ever count bits on their Millholland and other borers at the end of a shift.
Paper seatcovers, lots of chrome, and steady profits until a small dark cloud shaped like a Japanese car appeared on the horizon. “The Reckoning” would soon arrive.