Fords +
If you want cheap with marginal hp, forget the 8N. They are the darling of collectors now and decent ones get decent money. They were powerful in a small package
for their time, but were eclipsed by later models. I have an NAA (also called Golden Jubilee) only made in '53 and '54, and they are the consumate mowing machine. Again, because they were limited production some are selling for big money. A little later came the 600, which is the same tractor without the desirable badges on the Jubilee, so they are actually cheaper!
Even later gets more power and more transmission choices with the 800 series.
After that, go BLUE!
I can't stress enough about how you will really want a live PTO for mowing.
Early machines the tractor needed to be moving for the PTO to turn. Later, it was controlled by the clutch (NAA) -- somewhat better in that you could get the blades to turn by letting the clutch out in neutral. The best are true live PTOs -- driven regardless of what the transmission or clutch is doing.
With the early machines you need to get a free-running adapter on the PTO.
Without it, the momentum of the spinning bush-hog blades and disk will actually push the tractor even when you are trying to slow down! The free-running adapter lets the PTO ratchet so it can only drive and not be driven by the accessory.
Happy hunting!
If you want an early Ford, search for the
N-Newsletter published out of VT. Its for Fords only, lots of tech articles and lots of individual and dealer ads.