Call Pro-Comp and talk to them about it. Tell them you're concern, and ask them who they buy valves from. They don't manufacture them. They likely buy from Ferrea or someone like that. If they do, then they should be fine, if they can't tell you.... might be a red flag. I've got Pro-Comp rockers, and I called them one time when an adjuster broke. They were totally up front about issues with their adjusters, and reccomended I change them all out. They sent me a complete new set of different ones from a for free. My point is that I got good customer service from them, so I would just call and voice your concern and see what they say. My bet is that if they're marginal quality valves, they'll tell you.