Sun Ra Kat:
Once adjusted correctly there should not be a lot of change. In my opinion, many of these get installed incorrectly. Common mistakes: rocker-to-valve geometry incorrect (wrong shim); incorrect length push rod; adjusters tightened down too far. As bad as that sounds, when you see the oem rockers, you will wonder how they work at all.
Are you going to participate at National Trail raceway in August. Several of us are coming down on Friday. Get some tires and give us Northerners some competition.