I pulled over 36,000 about 12 times with an 86 3/4 ton fjord 4x4. Had a 351 w/4 barrel (all stock) with 33" tires (31s would have been better). Pulled gavity boxes filled with corn. Had to use 4 low to get it going, went 20 mph (any faster and the wagon would start hopping). It cost a lot less to run a pickup than to run a magnum series tractor. The old 656 gas job brakes were messed up and couldn't get the wagons rolling out of the field.
