I was thinking the other day about the PTOs on that era major, and how they're essentially locked to the gearbox input when engaged.
I dunno what kind of rotating mass your mower has, but there are PTO shafts you can get with sprag clutches built in.
Helps to avoid you disengaging the clutch, and the spinning mower saying no fuck you we're going to keep driving forward for a while.
I'm told the 'live' PTO and hydraulics on the later majors was a nice thing.