Iron W2 , Tried their web site, doesn't really give much info on the stx-21, and no mention of valve lash settings, I'll try calling them later today,
Thanks for the reply.
That is tight for an older cam. Their usually much looser like Rick said. But if that's what Jim said I'm sure it'll be fine. I've been running RB cams for a few yrs. now with great results.