The stock adjustable rocker set up with hydraulic lifters is a great set up and keeps you from having to change pushrod length to get the desired preload. Set each lifter on the base circle of the cam, run the adjuster down until you get to zero lash, (without compressing the plunger in the lifter) then add 1/2 to 3/4 turn of preload. It will be quiet and run for years.
