Depending on the displacement you are looking for - there are tons of 318 hyd roller motors in the bone yards, and 360's as well. If your motor is not already machined or otherwise ready to go, why not pick up a late model roller engine and do it to it. All you'd need is the short block.
i'm pretty sure the blocks are the same up to whenever the magnums came out. 92? the stock roller lifters are much different then the aftermarket jobs.
