Allis Chalmers 200 needs more power

A "stock" 200 tractor was 94 PTO HP.   There never used to be a problem turning out the torque screw several turns (or removing it and replacing with a plug) and getting 115 PTO HP. Takes 5 minutes to do. This assumes your pump and injectors are in good condition. More HP comes from more fuel. A better turbo won't change things much if any. Same for injectors unless yours currently have plugged holes.  Increasing the high idle really helps on forage equipment performance.

The torque screw is external and located just above where the lines attach to the hydraulic head. It sticks up/out at a 45 degree angle and has a plastic cap on it that unthreads. A 7/16" wrench and an allen wrench to adjust it OUT. Just remove the whole thing and adjust it 3 or 4 turns and replace. Swinging room isn't much on the pump. Removal of the pumps lid and governor guts is for roller-to-roller dimension and if your torque screw change isn't enough, that's where you go next. Remember your cooling system and tight fan belts. A couple hundred more RPM really helps on a chopper !!!

Are you trying to pull a 2 row chopper with a 200 if you are you’re going to need around 150 horse on the pto
A 200 will handle a 1 row very good but if you double the material going thru the machine it’s gonna be very slow
We went from a 1 row to 2 row on a 7010 and it was a load on it
A 7045 or 8030 will handle a 2 row really good

It all depends on your population and corn height. Chhopping corn in 1985 at 80,000 population is a lot different than chopping corn at 140,000 population. I've seen two row of corn taller than the tractor cab and 150hp could barely do. Go on the other side of the field out of the much chopping 6' tall corn and you had no problem and picked up a couple gears.