[TJ's Chevy]

Drive the truck for about 30 minutes. Shut the truck off...pull the valve cover...turn the engine on again and adjust the valves while the truck is running. Loosen until they clatter then tighten until they get quiet...then 1/4 to 1/2 turn from there to set the preload. Done it this way for years...people try to tell me I'm "inexperienced" for doing it this way but Whatever. lol Works and long as your slow it won't hurt a thing. And you'll hear when the rocker is to loose...the tap will become alot louder...just tighten until the tap is quiet and Right when it gets quiet do a 1/2 turn pre-load.