Better back the pump stops out first then...
I run a 3970 Deere harvester (the equivelant of the 900) on a Ford 7710 turned to 105 HP and it works her HARD... with half the knives. Full set of knives is doable but it's extremly hard.
The 2640 has nowhere, and I mean nowhere near the power or torque of a 7710.
I'm thinking it's about 70 horse? 4 holer, 239 and no turbo?
You'd get by with it in low gear, in a light crop with half the knives and that's about it. As they used to say about driving a Detroit... get in, sit in the seat, slam your hand in the door and drive it like ya hate... cause you're gonna have to hate her to make her chop silage.
You best cover the clutch pedal too so you can stop quick when it starts to plug... or get the rolls stopped quick before she goes down for the count. 2400 to 0 happens in about 3 seconds.