I had looked at it in the past, but I went back and re-read the Sanborn post. I did much of what he did, maybe not exactly the same way, but it accomplished the same thing. I was using a solid roller and bushed the bores. I also cut the oil to the left galley with a plug in the passage under the front main bearing. No crossover, no oil in the left galley. Sanborn mentions his engine oiled the top end through the pushrods, just like your Magnum, because of the T&Ds. We used Cranes and initially oiled the heads as originally designed through the passages from the 2 and 4 cam journals.

When we did the oil system, we took the oiling for the head away from the cam journals and restricted the amount of oil going to the heads. All of the oil in the right galley went to the crank and stayed on the crank with none being bled off to do something else, except for some lube for the cam bearings. We went from fixing a rod bearing every 7 or 8 runs to being able to run a full season without taking the pan off.