Depends on how you look at it I suppose. Mudra hired Ehrhardt as his assistant. Some say that Mudra was more of an administrator while Ehrhardt was the actual coach. When Mudra left, Ehrhardt took over the program.
Notwithstanding, until Mudra arrived on the scene, Bison football was a bottom feeder. Mudra took over a 0-10 team, turning it around to 3-5 in his 1st year (1963). In 1964 & 1965, under Mudra the Bison were 21-1. Ehrhardt took over in 1966. Ehrhardt won more games and bowls than Mudra because he was here for a longer run than Mudra, but it was Mudra's tenure that turned the Bison into the winning machine that it has become with 50 years of excellence.
Mudra's 1965 Bison team was something else. Awesome to watch. They steamrolled everyone and everything in their path - both offensively and defensively.