who is running MRL (BAM) Lifters without lifter bore sleeves

Any reason to not try a multiweight oil? Your straight weights oil are going to do just what you see, and the weight comparisons made by others here have not spec'd the weight of oil being used so that is not being factored in IMHO.

If you feel it is fully broken in, why not try a 5W40 or 15W50 synthetic? The synthetics have the common property of having much more stable viscosity over temperature change; they are more temp stable than the weight numbers indicate. They WILL tend to be thinner cold so oil pressure will likely be lower cold unless you use one of the heavier weights like the 15W50.

OH, I see Kimmer has commented on the weight.. same thought.