In 1970, the AFL was absorbed into the NFL and the league reorganized with the ten AFL franchises along with three existing NFL teams: the Baltimore Colts, the Cleveland Browns, and the Pittsburgh Steelers, becoming part of the newly formed American Football Conference.
The AFL and the NFL champions faced each other in Super Bowl IV at the end of the season to determine an overall champion.
Read More
This was a rematch of the first NFC Championship Game played the previous season in San Francisco. At the time, the NFL rotated hosting rights to playoff games between division champions. Under this format, the NFC East champion Cowboys had the right to host the 1971 title game. It was the fourth title game played by the Cowboys, and the 49ers' second title game appearance as an NFL team after the preceding season's game.
I sincerely appreciate the research work, and the information being shared. It is important and interesting history.