Terry told me before he pass that it was okay on a 426 hemi for them to rub a little, three burnt up single tapered exhaust pushrods later I ground more clearances into the KB aluminum street hemi block so they didn't rub at all. No more issues after that.
The bad part was some one else had bought all the parts but the pushrods and they bought a set of comp Cams solid roller with the pushrod seats .250 lower than standard, wrong parts for the Hemi blocks