Cams using solid lifters require a lash adjustment. Hydraulic lifters require a preload. Go to zero lash and then turn a little more in order to depress the lifter plunger about .030". Best to stick a dial indicator on the pushrod side of the rocker, and use that to figure out how much you have to turn the nut to move .030". But yeah, people have usually just grabbed the pushrod and wiggled it around to feel for slop while turning the nut in. Once the pushrod stops rattling, thats zero lash, and then go a little further, like 1/2 turn.
