I have a factory 380 hp magnum engine that I bought from a friend. The motor had been sitting in a crate for a few years. No complaints about the way it runs, it has plenty of power. My question is it sounds like a solid lift when its idling, not really a lifter tick, but a light rattling sound. I bought a set of Edelbrock heads and roller rockers. I thought that I could adjust the rockers to quieten the noise. If I adjust them tight enough to stop the rattle it runs crappy. A mechanic at a local shop told me to run heavier oil in it, 20w50. I am currently running Valvoline 5w30 semi synthetic. I don't really want to run that heavy oil. Should I invest in a new set of lifters, if so which ones???