That Walmart oil was bought for this old junkyard 360 with a million miles on it likely. Now of course I believe in zinc it's in all oil LOL. And of course I broke my new motor with 350 lbs open rate with penn grade break in oil and I've only used penn grade since. I'm not going to take a motor that's had 40 or 50 thousand miles on it that's been taken to Jiffy Lube all its life all of a sudden now you need some special oil with extra zinc in it LOL