Hi,
there are quite a few posts around telling you how to set your valves, all websites of cam-manufacturers (my fav is cranecams.com) tell you how to, too. But maybe it's not a problem with your rockers, maybe your lifters are full of oil? I had that problem, the previous owner of my engine (350 stock) "pumped them up" before he put them in. Thought it was the right thing to do. But then i had 4 of my lifters acting as if they were solid, that jolly well rattled my bones. so I took apart every lifter, cleaned it, just coated it in fresh oil and was very careful not to get any (except for lubrication) in the bottom of the lifter (where the spring is). works fine. Couldn't set it at all before, either too littler valve lash (RATTLE) or too much lash (duration too short, so I got no power and no high revs). now: almost perfect (there are other things wrong, but I guess that's settled now). Check it out,
MadMax.