What made this mark?
 

On my driver side, upper control arm paint is worn off to the bare metal. I thought was from my tire which appears slightly worn on the sidewall. But I got under there and looked and really it seems impossible that a tire could reach that far inside.
​​​​​​
Passenger side is normal. A few years ago I did have some oversized tires (P235-70) on it and before that he had a collision hard enough to break the grill and mess up the alignment.

Actually, I was hoping it was the tire rubbing and that rubbing was causing the whoo-whoo sound as I drive along. I bought some spacers but now, I don't see them helping anything.

Ideas as to what's rubbing?
https://cimg4.ibsrv.net/gimg/blazerf...9c8c29be68.jpg

It looks to me that it is the mud flap on the inside of the wheel-well that is likely the culprit. With weight on the tire, the upper control arm will come close to level and with the length of the flap, it will be pushed over the top of the control arm. Every time you go over a bump, it will rub back and forth, from inside to outside, slowly wearing away any dirt and some of the paint.

I believe the correct place for the flap is inboard of the the pivot points of the upper control arm.

Gosh Cristine, what a great analysis. With the wheel back on and the car lowered, yes, the flap lays right on the worn spots. The flap on the other side is missing, so that's why no wearing there.
Problem solved... now, what to do with these spacers...