If its just some heads from 93 or 94 they are not R/T heads. The R/T head did not come out till around the time of the R/T truck (99) and even then the R/T head was just an aftermarket magnum head NOT the one issued on the R/T truck. The R/T head has R/T cast in big letters right on the side.

As for stock rockers I have started having the PR push through the rocker around .550 lift and 10,000 or so street miles and hughes 1110 or 1111 springs or something close to that number, whatever it was hughes recomended. I would say .500 or so lift and matching springs would last a very long time. With real R/T heads 11s should be no problem with a well sorted combo.