my late uncle used to blend oil for Sunoco. some of u people are off on ur thinking, and a couple are just full of it, according to what he used to tell me. He did it for about 35 yrs., all the diff brands around here came right out of the same refinery, w/ just the brands additive bein diff. I`m running 20w50 in my 505 w/ tighter bearing clearance than I wanted. As soon as I think the rings are seated, I'm going to 20w50 syn. I have full time oiling to the top end, a lot of oil loss around the lifters because I couldn`t get the bores bushed around here-go figure.
