never had a mack , either had a gasser OR 300 cummins
m123 ment gasser, double winches
C model ment single winch, lower 5th whell
D model ment double winches, lower 5t wheel
A1 ment Cummins power, built with the cummins, not refitted
So a m123a1c was a cummins power, single winch, lower 5t...