How would the oil go up around the stud to get to the hole in the head. Many did different things over the years to get oil to the rocker shafts on the LA's.
I remember someone years back ran a line to the shaft. Worked great until the line cracked off. There have been so many trying to fix this problem over the years . Some worked and some didn't. Some were only able to be done at a great expense with special parts.
Indy and T&D told us we had to run sprayers.
The method I just shown you is what we were shown years back by a very popular small block mopar engine builder. It works great. It can only be done as per build because the stud needs to be indexed in the block when seated. So this prevented an Item that could me made and sold. No money to be made ? Why sell the idea if you'll lose money on parts you can sell.
This fix is just something inexpensive you can do when building your engine.