If the heads are set up for standard Mopar SBM shaft rockers, they will take the stockers. But it's also about stress on the rockers; the stockers can only take so much. That's not determined by what they are mounted to; steep cam ramps (Voodoos and XE cams), higher lifts, high RPM's, and heavy springs will push them towards overstress/breakage.
The OEM's survived in the 340's with mid 400's lifts, slow cam ramps, and moderate valve spring rates, so take that as a clue to what they can take. There is a reason that the heavy duty MP versions were made.....