McEnroe went on that year to what John Barrett of the BBC called the most perfect Wimbledon two-weeks he'd ever seen. McEnroe demolished Connors in straights at both Wimbledon and later Lendl at the Open. Against Connors, he won 1,1, & 2; Lendl 3,4,1.
I agree that it's going to be nigh on to impossible to equal McEnroe's 84. But, if Federer can maintain his current level, it's possible.