You look at guys who run small block Chevy engines way back when with the stock press in rocker arm studs, and think about where this need to constantly reset the lash stories came from. Stiff valve springs and high rpm have been known to pull those press in studs up out of the heads a little bit at a time likely creating a need to set the lash more often. A Chrysler engine with the rocker shaft setup is likely going to be more stable compared to other engines.

There is a good thread about solid flat tappet cams on the street on the H.A.M.B. website where guys are logging some decent street miles with few if any adjustments being required. Not race spec cams, but street type configurations.