"And just how would you drill those feed passages in a solid steel block. You would need specialized tooling to do it, and if you got it wrong you will ruin a very expensive block."
I know - that's why I said it's tricky. The block is iron, not steel, which is significant as iron is a little more forgiving in this regard. I 'could' drill this by setting the block up in my mill, and I'm confident I could do it successfully. But like anything....it might just be a lot of trouble for no real gain.
If I were a Larry Atherton in the 70's, I would just ask Chrysler for a new block if messed one up. But I ain't, and I'm working on a block which has become near-unobtainable.
When I made the clutchflite transmission, I had to drill a 15/32" hole very accurately through solid aluminum for about 7". I took my time in setting everything up and used all the right techniques and when I was done the hole ended up less than .005" from perfect.
A bigger issue lies in the shadows, if a person were to attempt do this. The right galley is fed by a 1/2" diameter hole, or at least it is once we drill it out to size. But feeding the left side? Very tough to find a way to feed it with a hole that big. Another good example of Mopar...they give you this nice big front feed port on the right side, but nothing on the left....even when it would have been very easy to add a pound of cast iron in the right place. Or they could have easily added meat in the rear of the lifter valley.