A lot of effort needs to be utilized to get oil back to the sump in any engine-no matter whether its high pressure, volume, etc------No matter how long or from what pressure oil setting in the cylinder heads instead of the sump is not good. As for FE engines the absence of the OEM drain back trays is a mistake--------and if you want to restrict flow to the top you better have Erson roller rocker shafts, plus drainback system.