rocket arms coming off

Now that you have specified an 8 cylinder engine, I still suspect bad/sticking lash adjusters or low oil pressure to the heads. The oil passages are relatively small and may become restricted over time if the oil is not changed frequently enough to prevent sludge buildup. Another primary cause of sludge buildup is operating at cool temperatures as in many short trips or a bad thermostat not bringing it up to normal operating temperature. If sludge is the problem, you may be able to help by using an engine flush additive to clean it a bit. If you are using anything other than a high quality 5w20 oil as recommended, the oil may be a bit too thick to circulate with restricted passages. With extented hot operation, it "may" get better. If replacing the lash adjusters and going to a lighter grade oil does not do the trick, you may be in for oil pump replacement or engine overhaul. If it is the same follower coming off, I would start by replacing the lash adjusters on those three, running an engine flush, and putting in a good quality 5w20 oil. If that doesn't do it, you are in for heavier repairs.

Lugnut