I been studying hard the oiling in my stroker I am building and it seems the full groove would help the rod bearings live longer because they have access to pressurized oil when the cylinder pressure is highest. The 1/2 groove only sends pressurized oil to the rod on the bottom half of the stroke. Weather or not that amounts to a hill of beans under dynamic conditions I could not tell you but it does seem odd they do it that way from the factory.
In order to keep more oil on the crank on mine I drilled smaller oil feed holes in the cam bearings as they are getting fed right off the oil going to the mains. When everything is done right in a SB oiling don't seem to be a big issue from what I have seen. I almost always use standard volume pumps and don't seem to have much issue getting enough pressure.
The issue is the oil timing is wrong on these engines. You should have full oil pressure to the rods at 70* ATDC and that is IIRC but it is close to that. That's why a Chevy doesn't need full groove mains. The Chryslers get full oil pressure way before they need it so the full groove mains helps that. Seems to be worse on the SB but it is wrong on both. The higher the engine speed, the worse it gets.
There are only two fixes for the high rpm stuff (unless you get a block that has the oil passage in the correct location).
One is have a crank drilled with the oil hole turned counterclockwise. The other is more complicated. That is the only way I know to correct it.
