I agree completely with Kunderblunker here.
Bock wins this matchup each and every way possible. He simply was one of the greatest World Champions that ever lived. He would have been NWA champion when it was the most important title in the business. He didn't want it because he could make just as much money as AWA champ working his own schedule. One of the main reasons that Jerry Jarrett gave for seceding from the NWA to partner with the AWA was that Nick Bockwinkel was a better World Champion. He is criminally underrated around these parts, and if not the favorite in each of his matchups, he should always be considered a very legitimate threat to win.
But Mad Dog Vachon was a hell of a lot more than just a 'good hand'. He was one of the best heel wrestlers of all time. When Verne wanted to give himself a rest from being Champ, it was Vachon who he trusted to keep his business thriving. The fact that they kept going back to him (5 time champ in the 60's), was a huge deal. That just wasn't something that was done. It spoke to the talent of the guy that they would keep going back to him, and that he'd keep staying over and be considered a legit champ or threat to the title despite losing it so many times. Usually back then, one short reign, and someone was done as legit champion material. Not the Mad Dog.
His staying power was enormous. So much so that even today, he's still remembered fondly and his name is well known... when most of his peers have been long forgotten. Go ask 10 people if they've heard the name Mad Dog Vachon. You'll probably be surprised at how many have.
He doesn't win this matchup. Like I said, Bock was just on another level. This is a classic AWA matchup that actually happened quite a few times too, and Bock almost always came out on top in those (and if he didn't, he was DQ'd). But if you could promise any professional wrestler that they'd get to have the career that Mad Dog Vachon had... every single one would take it.