I believe that was the T-41B. The T-41A had an O-300 and a fixed-pitch prop.
https://en.wikipedia.org/wiki/Cessna_T-41_Mescalero
I got a few hours on a T-41A, back as a CAP cadet in the '70s. Don't remember the engine, but it did have a fixed pitch prop.
Ron Wanttaja