Oil change question?

[BWG56]

The bullshit ends.
It's perfectly ok to use synthetic oil in your EVO type, S&S , Ultima, Twin Cam, and most any other internal combustion engine.
If it leaks past any gasket, or seal, you've had a HACK work on your stuff.
I wouldn't consider using anything but synthetic oil in anything I drive on the street.
John

Or my lawn and the mountain trails