Seems like most Watsons of the era have an OD, mine is 0.85. Model 43. I don't know about model 42m.
Easy way to figure out before purchase, mark input and output shaft to the Watson and jackup a rear wheel. Main trans in neutral. Turn the wheel and count the difference in shaft speeds. A single rotation of the input will get you a good idea of ratio difference, for more accuracy do multiple rotations and a little fractional math between input and output rotations.
Good luck
Last edited by Cornerwindows; 02/03/2012 3:02 PM.
