Back in the day, my '68 Ram Air Firebird only had about 30K miles on it when it shucked all the teeth off the cam gear. A common problem with Pontiac engines back then if you were taking them over 5K rpm very often. Pontiac's replacement timing set at the time had steel tooth gears rather than the nylon tooth cam gear. It made no more noise than the original one. I've never put a nylon tooth gear in an engine since. Never had a problem since.
I've found with two engines, that, in cleaning the block, the shops would never wire brush out the oil galleries and do a good cleaning. After being hot tanked, the galleries are still full of loosened up crap. Put the engine together and all this stuff goes right to the bearings and lifters. I used to wire brush and varsol all the passages and it was amazing at how much crud came out. On the flip side, my engines never had bearing problems and lived long happy lives. One old engine guy used to say that cleanliness is next to godliness when it comes to putting together a good engine. I always remembered what he said.
