Requested oiling mod info

What book is this? Also, do you do both the tube and lifter valley crossover together. I have engines with just the crossover.
No, that's 2 different methods, as per the text.
The tubes aren't BS, but are primarily for using roller cams, which would usually expose the very large & low gallery portion of the liftr bore. The crossover was found to increase main oiling according to some Super Stock racers, and reputed to reliably operate to 10,000rpm, with solids of course. Whether reliable hydraulic tappet operation gets a big boost or not would have to be shared from those who have done it w/hydros, I have not.