I recall remarks by David Vizzard about how different oil formulations (same weight) affected lifter function. I wonder if any difference would show up on the new Comps.? Might be interesting, but very time consuming to do all the testing.
I have installed several sets of Morel hydraulic roller lifters in builds this summer, Pontiac, GM and Mopar. Instruction sheet with the lifters mentioned required centistoke rating of the oil. After researching the spec, 10W30 oil is the thickest recommended. In comparing the lifters run quieter and oil better to the rockers with the thinner oil. I had been using 20W40 Rotella as a break-in oil. I changed to a mineral based 10W30 oil.
