On a all iron cold motors (heads and blocks) with hydraulic lifters and adjustable rocker arms like yours I like and use between 1/4 to 1/2 turn preload from zero I have seen recommendations from some of the cam grinders to look for .015 preload cold on a all iron motor between the lifter cup and the retaining ring on top of the lifters when adjusted cold with the intake off
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
I have seen recommendations from some of the cam grinders to look for .015 preload cold on a all iron motor between the lifter cup and the retaining ring on top of the lifters when adjusted cold with the intake off 
