I don't know if you thought about what took out the cam lobes with only 5000 mi.or if you have kept up on what they have done to the oil. They have taken out the zinc to help the catalytic converters, which does not bother a roller tappet motor. But it is eating up flat tappets faster than you can put them in. There is an oil that they did not take it out of, so do your home work before putting oil in a new rebuild. There is an additive to. 36Fred