I think a lot of the bigs back in the day were built more like the players that we consider power forwards now. Dirk/LMA/KG etc, but they didn't have the shooting range.
wut? the year the Blazers won the championship, the C's in the NBA included Kareem, Moses Malone, Artis Gilmore, Bill Walton, Swen Nater, Elvin Hayes, Wes Unseld, Bob Lanier, Billy Paultz, Kevin Kunnert, Caldwell Jones, Clifford Ray, Jack Sikma....
5 years before that you had many of the same guys listed above plus Wilt, Thurmond, Elmore Smith, Walt Bellamy, Tom Boerwinkle
in the middle of the Drexler era, there were Hakeem, David Robinson, Patrick Ewing, Rony Seikaly, Moses, Bill Laimbeer, Parish, Benoit Benjaman, Rick Mahorn, James Donaldson, James Edwards, Mark Eaton....
sure, there were PF's masquerading as C's like Dave Cowens, Alvin Adams, Sam Perkins, Dan Issel. But those were the golden ages of true C's. The introduction of the 3 point line and all the defensive restrictions have torpedoed the value of traditional big men, but I'm not convinced the NBA is better for it