Serveral possible answers as to why it blew:
1: Bearings installed incorrectly
2: Bearings installed DRY with no assembly lube
3: faulty oiling system (bad pump, blocked oil passages ect....this could go along with #1, Bearings installed backwards ect could block the oil passages that feed the bearings.)
4: Bearing tolerances could have been too tight or too loose.
And the good Lord said unto John "Come forth and ye shall receive eternal life." However, John came fifth and all he received was a goat.