I am going to go back a bit in the 50's we had gas and or distillate engines,
in the 60's and 70's up to 80 HP you had a choice of gas or diesel, depending on the make and model the gas and diesel turned about the same rpm (within a few hundred), the power delivery was very similar the gas motors had about the same lugging power as the diesels.
A lot of the gas engines had torque peaks at 12-1400 rpm and would pull right down to 3-400 rpm,
then of course the poppin johns would lug down to just a few rpm gas or diesel.
The gas motors generally started better, especially in the cold weather,
most of the diesels had a bit better longevity, but also cost more,
the big difference was in fuel usage, the gas engines used a lot more gasoline to do the same work in a day then the diesels used,
especially when you went over the 60 HP level.
The cost of diesel was a bit less per gallon, I can't recall the exact $$$.
As time went on the diesel economy surpassed the gas by an even larger amount.
It would be interesting to see a gasoline tractor with the newest injection technology and ignitions, to compare with the new diesels.