John,

That looks like a 4240 to me, but a later one with the larger tail wheel. I don't know why it is red now, but it would most likely have been green with white wheels. I'm not sure if they made any big tail wheel 4240s with green wheels.

The sales literature doesn't mention a break away hitch, as these plows came with trip back bottoms. So they wouldn't have needed a breakaway hitch. The dealer price sheet I have from 1960 does not show the breakaway hitch as an option for the 4240.