[kamkam1]

Thanks for the replies, I'm running roller tip rockers and Z-28 valve springs good for .525 lift. All rockers are oiling good. the engine has about 1000 miles on it and the truck has been setting in the shop for about a year. After the engine was built about 2 years ago, on initial start-up it popped thru the exhaust during cam break-in and I blamed it on bad gas, so I drained the fuel tank and put in fresh gas and the popping started going away, so I thought the problem was cured. The truck ran fine for several trips down the track until #7 exhaust started rattleing. Fast forward to this weekend and the new cam, it popped thru the exhaust during breakin . After breakin I checked valve adjustment and all was fine, but the valves were still clattering, so I decided to set the valves while the engine was running and when I removed the driverside valvecover and start the engine BAM what the hell, #7 exhaust valve lobe gone again. I'm thinking valve springs?? Oh the cam has .477/.480 lift. Later Kirk