6 playoff appearances, 4 World Series appearances and 2 championships (BRM).
Oakland did have a ridiculous run from 1971-1975 (including 5 playoff appearances and 3 championships), but they were non-existent for the latter part of the 70's whereas the Reds were competitive for most of the decade.
Pittsburgh and the NYY won 2 championships as well, but their competitiveness in the 70s were not as impressive in my opinion.
What do you all think? I admit, I was not around watching baseball in the 70s, but based on numbers, it looks like it comes down to Oakland vs. Cincinnati.