Ok Comp Cam 280 w/.480 lift hydraulic cam, 882 casting heads with 2.02/1.60 valves screw in studs and guide plates (heads came factory with this stuff), Competition producs valve springs, retainers and locks, brand new stock type rocker arm nuts from NAPA. I drive 7 miles to work and they are out of adjustment. WHY? This is the same same combo I ran before I had a fresh valve job done, replaced valve springs, I adjusted valves using stock nuts and they clattered after driving for a day, now its worse. I drive to work ok at about 3500 plus rpms and I get here and the rockers are loose?? I know poly locks but then I need to get tall valve covers since I have the factory 74 Z28 aluminum valve covers with the little dripers inside and they do not have enough clearance for poly locks. And good tall aluminum valve covers are $100-200 or higher if you want the really nice GM ones. Any reason why? will poly locks solve the problem?