My take on the oiling system crossover tube for the small block
I can say without even blinking that a crossover tube is worthless. It does zero. Except put extra holes in the block. That "fix" was never a fix and should be forgotten about.
The oiling system is a simple hydraulic system. All that bullshit about the oil moving too fast to turn down the feed is just that...bullshit. Or a lie.
Any engine running solid lifters of ANY kind should be tubed or bushed. If you want to run pushrod oiling, then drill a .0625 hole in the bushings or tube where it passes through the lifter bore and run it.
If you have your **** together, 7500 RPM with a QUALITY oil pan, a HV pump with no less than 80 PSI at WOT and full groove mains is doable. Any more RPM than that and it get iffy. Over 8000 and you need to correct the oil timing.
The crossover is just doing work to make someone feel better. Doesn't do a thing.