Problem with big clearance and a LA Mopar is delivering enough oil to the mains. If you block off the DS lifter feed you increase some. Drill all the main feeds helps. Restrict the heads also helps. Deep pan to accommodate all the drainback.

Easiest thing is don't over clearance the mains. .025" is minimum on a 340 main imo. But, .003" will keep oil blowout to a minimum and feed the larger rod journals that are likely overclearanced to. I have had many shops laugh when they saw my P bearings in a high HP price. But, after seeing the condition of my bearings was told don't change a thing.

My theory... They oil the rod 360°. This can also cause oil loss. But, I never had hurt a main. Hurt rods but not mains in early builds. I dealt 360° rod oiling cooled the bearing. If the bearing runs cooler the clearance can be tighter.

Just what has worked for me.