Oil modifications.....why and how to.

The issues most of enthusiasts will hit is more related to poor machining than poor oil system design. Some certain parts or performance goals will need more than this. In terms of "secrets", for every engine there's a few things I do...
-I drill the filter adaptor plate so there's at least (8) 1/4" holes in it.
-I enlarge the main bearing feed passages that come down from the lifter galley to 5/16, which is the size of the oil hole in the bearing shell.
-I drill additional drain holes in the valley area so oil can get down to the sump faster.
-I deburr and shape the valley holes to remove any restrictions to the oil return.
-I use a carbide burr to carefully elongate the holes in the cam bearing backing.. Not the hole itself, but the steel backing.... so oil can flow through the hole much easier and make use of more of the passage.
-I use the best machinist I can find, not the cheapest, and I own the correct tools to measure everything properly. I also write down everything I measure.
That last one will go the furthest to helping survive. I don't feel taking hours to shape every passage or increase the oil volume beyond what I noted above has any real return, as there's thousands of engines that never had it that do just fine.