273 rocker arm adjustment

x3 on the banana grooves. There is no good way to help spread the oil out under the rocker without it. The stamped rockers had a radial groove in the rocker itself to help spread the oil around.

IIRC the shafts for the stamped rockers have a larger oil hole just like what you show for the rocker than the original shafts for the 273 rockers. So you may have ended up with rocker shafts for stamped rockers. (I have some new MP shafts here which also have the larger holes.) Not sure it makes any difference for surface hardness, but the 'it's OK because the hole are bigger' sounds like just made-up advice for oiling the 273 rockers with high spring pressures.... IMHO.

And I am kinda leary about the 20W50 oil...it is going to be another restrictive matter in delivering oil to the shafts and rockers. That area is low pressure and low volume already and there already 2-3 restrictions in the path from the crank to inside the rocker. The ARP studs narrow down one more area through which the oil has to flow so that adds more flow resistance. If there is no other compelling reason to use 20W50, I'd consider dropping to 10W40.

But at least the pushrod cups sound like they are doing well now; that's a big step forward from a couple of years ago!