My dad had a ferguson TO30 he would use to chop the grapes, its about the sive of the old fords. It worked great but it was like cutting tall grass. A over grown field and its goes slow. Just today he was talking about when he mowed 5 acres of tall dry grass for my uncle and 3 times he steped on the clutch and teh mower plugged up with grass.
I just cut about 3 acres of tall dry grass with my 484, when its dry it really takes some HP. My dads 75hp JD with a 5ft will shop anything at a idle and never bog down.
If you can Id go bigger, its worth the extra money. I have about 3k into my IH but have a million hours into it. I see alot of fords, like a 8n for $2500. My IH is twice that tractor, if not more. Also get a diesel if you can, the torque of the diesel makes the tractor seem like twice the HP of a gas the same size.
Those old fords are good machines but just slow because of low HP and no live PTO. Maybe get one of those fords with the flat head V8.