You will get a million opinions on this, lol. I have always said that over the years I am pretty sure these motors have been run on most every kind of substance, and some motors that I have taken apart I swear were run on sawdust! that being said, with the cost of rebuilding a motor these days, I switched over to 10W30 BradPenn (now called PennGrade1). Its a Pennsylvania crude based oil with a partial synthetic package. It is refined at the same refinery that made Kendell's famous green oil (its till green) and it has a zinc package added to it. I tried it a few years ago and discovered that after the car sat all winter, when I pulled the valve cover to give it a spring lookover and check the valve adjustment, the oil was still clinging onto the rockers and springs. I also use their break in oil also. I have four 235/261 motors that I built, broke in and still run on the stuff, one of them, the last one I built (a very modified 261), gets a little abuse and no issues whatsoever so I tend to stick to what works for me.
Last edited by Dragsix; 03/26/2018 3:02 PM.
