Hydraulic roller cam and stock rocker arms

You could totally do it - here's how - Dart6 is on to it with the modern magnum setup!

Roller cam in your choice of specs (probably need to be safe and be well under .600" lift) -
roller lifters
rockers
custom length oil thru pushrods - here is where it gets tricky you will need to measure the pushrod length in mock up stage and order custom one's through the many makers

You need to drill a hole in each rocker- pushrod cup, and then weld a small metal tab over the hole on the top side of the rocker to deflect the out going oil from the pushrod (so it squirts towards the rocker shaft, instead of straight at the valve cover)

Like said lifter preload comes into play - you simply use the pushrod length to set lifter preload - that is how the modern factory roller cam, Mopar, Chevy, and Ford's do it - only they have a much weaker pedestal style mounting rocker.. (everyone usually converts them to the Chevy/Ford 3/8" stud mount and runs Chevy/Ford roller rockers in Magnums)

But that is how it's done.. - far less work to me than modding stock rockers with adjusters as you would still need to measure for custom pushrods