Complex sentence: Heisman moved from Clemson to Georgia Tech in 1904, where he coached for the longest tenure of his career (16 years) and had his finest success, achieving a 77% winning percentage and winning national championship in 1917.
Split into simpler sentences: Heisman moved from Clemson to Georgia Tech in 1904, where he coached for the longest tenure of his career (16 years). He won 77% of his football games, and had his finest success, winning a national championship in 1917.