Yellow rose I said I hurt 2&4 mains because I put in a full grooved cam. That groove removed the restriction to the rocker gear.
There was full time oiling to the rockers. That lack of restriction bled off too much pressure from the mains and they got warm.
This happened in a tubed block with a high volume 70 psi pump.
It is a textbook example that pressure does not always go everywhere. The lack of a restrictor allowed the oil to bleed upwards
To the rockers through the grooved cam journals.
Now if you understand how this happens you should be able to understand that the crossover does the same thing. It redirects some of the oil volume.