I'd have to go with SB IV, when the Chiefs beat the Vikes. As we know the Packers had beat up on the Chiefs and Raiders then here comes Broadway Joe and that Jets win. Now it's NFL 2 AFL 1. If the Vikes had won the following year, it's NFL 3 AFL 1 making that Jets win looking like a fluke and a freakish occurance.
In that game it was real obvious the Chiefs had the faster more athletic athletes. Big and fast Otis Taylor (Prairie View) was simply too much for those Vikes cornerbacks. Taylor was unlike anyone in the NFL at that time.
So after the game the NFL got nervous, so here came the merger. They ended up sending Cleveland, Baltimore Colts and Pittsburg (back then they sucked) to the now AFC. Giving each conference 11 teams.
The thing about the old AFL was their mix of HBCU athletes and big school guys, something we didn't' see to the same degree in the NFL.
I do think things would be cooler if we had never seen the merger. Not a fan of interconference play. I prefer the mystery. Now we can sort of gage things because this AFC team beat that NFC team that beat......
Prior to the merger there was a lot of....????? How would big Cookie "250 pound fullback" Gilchrist do vs NFL defenses? Could that Tobin Rote, Paul Lowe, Keith Lincoln and Lance Alworth Charger offense burn NFL defenses like they did AFL?