With ancient motorcycle experience, I have a hard time trusting external oil lines- which often cracked at a critical time. If you use dash 8 or dash 10 Aeroquip flex lines, I suggest strapping them down every 8" or so. On another brand of engine, I had an external Aeroquip line move a full 4" to be sawed open by the alternator fan. I think first I'll explore what the '69-early '70 Cleveland blocks had- extra drain-back drillings in the corners of the lifter chamber, and maybe enlarge the ones in the center. Also, someone decades ago suggested drilling BIG holes thru the frontside China wall to drain onto the timing chain and down into the sump.
I don't have an early block for close examination, only a photo (the extra drains looked about 3/8" ID which might not do much & maybe why Ford and NASCAR dropped the idea). I don't know what's involved in drilling such deep holes thru a cast iron block, or if the early blocks were cored differently. A good winter project for me on a junk '73 block in the pile. I'll report back when I try it. Would hate to hit water halfway through or weaken a rare usable block!