[KirkEvil]

Rule out exhaust leaks before getting under the valve covers.

When I had an ls1 lifter go bad, I could hear it at idle. The ticking got progressively worse over about a week of daily driving, and it was very loud. Like you coul hear the car from down the street. Hopefully that doesnt happen to you.

If you can get a buddy help, unbolt the valve cover then hook the coil packs back up. have your friend hold the packs above the rockers and start up the engine and give it a little rev to see if the noise is louder/coming from the rockers. Dont do it too long though because you'll shoot oil everywhere.

If you cant determine if its a bad rocker, time to pull them off. Check the needle bearings on the rockers, and pull the pushrods. Roll the pushrods over a mirror to check for bends.