Where I come from, the class is identical and is allowed a 3" x 3" slotted (Precision brand) turbocharger. All the best ones are making 1,000 HP or a little better. They are running 20.8 x 38 rear tires and in a gear that is faster than a 7040 PD roadgear.  The best PD clutch AC made was in a late-model 7580 4WD. It had 5 discs in low side and 3 discs in high side. I believe that it could be made to shift on-the-go (with valving changes) and hold the 1,000 HP. I don't believe that you could ever make it last very long with a standing start at 3,000 RPM in a gear faster than 5th (roadgear). That particular wet-clutch design will only stand so many degrees of heat and "bam" it will have warped components on the low-side clutch. it's kind of like wax or solder.....now you see it....now it's melted. Changing to a good multiple-disc dry clutch on a steel flywheel will last long and take the punishment. You'd need to design some sort of an input shaft to connect the flywheel to the high range input shaft in the transmission and then to seal off the clutch cavity from tranny oil. You'd also need a throwout bearing/linkage set-up, or maybe consider going to a Crower style RPM activated clutch. The range transmission gears in a Power Shift tractor are 20% faster than a Power Director tractor, so that would be a good place to start....a Power Shift rear end from a 7045 or 7060 tractor, as they have the fastest gear ratio final drives and range transmission.  Your engine configuration (inj pump, injectors, turbo, camshaft grind, camshaft timing, etc, etc, etc) needs to be tailored to be able to "lug" really well, because you don't have an on-the-go feature.  Get out your check-book and I'll help you spend it !!!!!

How does a power directer work? What would it take to straight shaft one? Do you have any experinece on water injection. Going to run D 21 intake mainfold and inject in cross over pipe.