my last 273 came up with bad rod bearings , but I didn't build that engine and it had sat for 27 years in texas. it was a fresh rebuild then from what I could tell. it evidently had some oil issues. but all in all , it's how you build the engine and how high you build it to rev I guess. don't use too big a cam that you have to rev it to the moon . take it to stock specs if you want it to last .5200 stock commando .