Sir;
My old D14 ( a '58 model) is the toughest tractor I've ever used... I've been a MF man all my life, but picked up that D14 for $700 (couldn't pass that up). Of course, it needed overhaulin', and the shift fork on 1st gear was chewed, so it needed building up - along the way, I've replaced a gear or two, and rebuilt the hydro.
But - before I rebuilt it, I pulled my dually flatbed - with a gooseneck behind it, loaded full of logs - out of a mud hole. Since I was by myself, I put the truck outta gear and pulled it up a hill with the D14....NO PROBLEM...I guess the rolling weight at around 10,000 lbs. But that ain't all....when the engine was torn down, two pistons FELL outta the sleeves...there had been next to no compression in the 2 & 3 cylinders at the time!
Allis made some dang good engines I'm sayin'...You won't go wrong waiting to find a good'ern.
SM