I've had and worked my share of gasoline old tractors, from JD A's, B's, JD M, 40, 430, Ford 8n's Ford 4000 INdustrial..
And you can have 'em all.. for WORK, nothing beats DIESEL torque..
I had a JD 430, 2cyl upright engine, a '59 model, I had a 6' ford Flail mower on it, a real HP HOG.. the engine was rated at 29 or so HP..
When the grass was tall, it would not pull the slight slope in my back yard, I'd have to lift the mower to lighten the load. I'd have to run
the engine at full throttle all the time to pull the mower,
So, I bought an 'early '80's JD 855, a stick shift, 3x3 speed, live pto, and mid pto 4x4 tractor, Power steering, syncro on all gears.
The engine is a Yanmar Diesel, rated at ~28 hp..
When I put the Ford Flail mower behind it, the tractor would pull that hill at less than full throttle with any amount of grass, in fact,
the Ford Flail would siip the drive belts if I loaded it too much..
There is nothing like good modern diesel power..
NOW electronicly monitored, EPA restricted diesels with afterburners or requiring UREA or all that other crap, is just that CRAP,
Diesel 'pollutants' are mostly carbon,, and carbon is the building block of all life,, it's almost pure carbon.. totally harmless Unless
you fall into a swimming pool filled with carbon dust,, then you might drown in it.
I LOVE my diesel JD, and as much as I like the old iron, it's more of a play toy when you really need to work, like plowing old fields,
or pulling a heavy disc, or Haybining heavy Alphalfa.. That's diesel work..
Just my crabby, grumpy old man opinion..
OH, I borrowed a neighbor's '60's ford gasser the other day, since he'd borrowed my post hole digger and it was on his tractor, he still needed
it for a few more weeks, but I had a hole to dig. so I went next door an borrowed the rig.
What a gutless tractor, I think it has half the torque of the little Yanmar diesel in the 855..