well the arm that rubs on the cam to trigger the valve to go up and down randomly decided to pop off on my Z (just one of em) made a terrible screeching noise and absolutely killed all the power in my car, any reason why it did this? reccomendations as to what to do next? nothing seems broken or ever scratched. All input is welcome

Had this happen to me a couple of times, but the car had been sitting for 20 years and I figured it was caused by a sticking valve, ran some Marvel Mystery oil and the problem went away. Car been sitting a while or is it a daily driver?

been sitting since 99' and it has 150k miles on it so it is most likely that... thanks where can i get that oil?

most any auto parts store(chains or local), sometimes even hardware stores.

it turned out the adjustments for the arm somehow loostened up and it just popped off, so i adjusted it and tightened it back up and all is well. thanks for the help!

When I bought my 280 in 1997, it had that same problem. The PO had parked it because he thought it had a major engine problem. It only had 69k mi. when he parked it. I put the rocker back on, did the adjustments on all of them and it's been fine ever since.