I have a Chevy 230 that was rebuilt 5k miles ago. Ran perfect until I accidentally tightened the rocker nuts thinking they were loose (coming from the nailhead world, I mistakenly assumed they were on a shaft). I realized right away and backed them all out and readjusted to 1 turn past zero lash. I've had a ticking ever since. I tried 1/2 turn past lash, 3/4 turn, adjusting while running, etc. Still chatters. I decided to pull the rockers, push rods, and lifters out to inspect. I found that the rockers had what looked to be fairly deep grooves - I have no way of knowing if they were replaced during the rebuild. The tops of the valves were flat and edges sharp (worn down?). Here are some pictures. Does this look right to you? I'm considering buying a new set of rockers. Not much I can do about the valves at the moment if they are indeed bad.