You broke it in 580 miles ago. Shoulda caned it back then - anything you do now is kinda irrelevant. Rings would have sealed according to the heat and use you gave it back then.

Just cane it. But if you have been gentle to it, then at WOT ring seal might not be as good as it could be

 

I know GM has for many years used propane and i think regular oil for break in, then they are crated to final destination. I have always built the traditional sbc on the tight side and used 20w50 valvoline to for break in through first tank of gas and never a problem. It's not how hard you beat on it and when, it's how well the engine was built!!

 

building a tight motor and then putting 20W50 in it? good god man! The engine probably lasted just fine but you didn't do it any favors by putting that thick of oil in it

 

Breaking a motor in on synthetic was a myth, it is not harmful at all. I've done it on factory engines and hand built "performance" engines as you call them. And I beg you to tell me the difference between a LS7 and a hand built performance engine. There isn't, and there is not enough difference in the rings to make it matter.

 

this.

a new engine will do 1 of 2 things regardless of what oil you use...

break
break in

 

The rings are seated before you can even burp all the air out of the cooling system... Beat on it...

 

You guys harping on zinc are old school. That was because it was critical to breaking in those old flat tappet camshafts. It is not necessary on a hydraulic roller......