I'm pretty sure the two did team; probably a few times over the years. Think I've seen a couple of cards from NYC with the two teaming. Of course, it's been so long since I saw it, it could have been a Pittsburg card, or Philly, right?
Bull's 'face turn came very late in his career in Detroit/Toronto, and to this day, I'm not entirely certain how it happened. Supposedly because the Sheik was mauling Freddie, but that happened a few times over the years, so why that one particular time? But then, a lot of the Detroit and Toronto angles didn't have a whole lot of logic behind them.
-------------------- The Traveller a fan since '68....
"Reputation is what others think about you. Honor is what you know about yourself. The friction tends to arise when the two are not the same.... Guard your honor; let your reputation fall where it may."
Bull and The Sheik did meet in the Farhat Promotion in the late 1960's. While still rough and tough, I think Bull became more of a favorite of the fans when he teammed with Fred against heel teams such as the Hell's Angels. That continued when Bull would meet heels in singles competition.