I have been told tales by old school Pittsburgh fans about the Steelers between '74 and '76. I only know these teams from NFL Films, but I did watch a couple of games of the '79 Steelers so I have an idea of how good they must have been.
Defensive Line - Mean Joe Greene, L.C. Greenwood, Dwight White, Ernie Holmes
Linebackers - Andy Russell, Jack Lambert, Jack Ham
Secondary - Mel Blount, J.T. Thomas, Mike Wagner, Glen Edwards, Donnie S
That defense would maul these current Patriots. You stick Mel Blount on Randy Moss and let that monster defensive line go to work. The linebacking corp is arguably the greatest in history.
The '07 Patriots couldn't even score in the second half against a 1-14 team. Their vaunted offense was stopped cold. Imagine what the "Steel Curtain" would do to them.
And there are at least five or six other teams in NFL history that would do the same to the '07 Patriots.