if they are stud mounted you have to set the lash. Just twist the pushrod between your fingers as you tighten the rocker down, as soon as you feel some resistence in twisting the pushrod, you are at 0 lash, tighten down 1/4 to 1/2 turn more and lock the rocker down. Of course this has to be done in a certain sequence to make sure you are on the flat part of the cam lobe for that rocker, im not familiar with the 302 sequence, but that is the way to "adjust" them.
If its pedestal mounted, then im not sure because i have studs.