When I called Valvoline and asked them about their Not For Street Use oil they said it doesn't have the additives for street use. You would have to change it every 500 miles. This is what one of their techs told me.
Its been working just fine for me and I leave it in for 4-5 months, like 3000 miles.
It has to be fine, you can not believe everything some tech guy says. Its very high in Zinc, I notice the oil stays cleaner longer. I swap heads this fall, my motor look very clean inside. My little 318 revs to 6200 almost every day the weather is nice.
I had a Summit Racing tech trying to tell me a MSD 7al box would burn up on the street, mines 3 years old now, still going just fine.