Research for a project.....

Okay, ever since I swapped out the original 3000 (according to the block casting) with a Ford/NH 4630 engine last year on the Chisholm Ryder grape harvester, I have a 'spare' motor that needs to be taken care of.

My original idea was to rebuild it and set it up on a stand (as a running engine) and back up for the grape harvester. (Other problem is to find a bell housing so I can do this project- like on industrial engines, has pto unit).

Any how, according to online specs, the 3000 engine was rated at 47 HP, while it sent 'only' 38 HP to the tractor PTO. Specs also say that this engine is a 172 (2.8L) engine. And under the old 4000 specs, the engine is a 175 (2.9L).

This engine is a 'backup' to the 4630, just in case- but I want it built as a runner. Original planning was to hook it up to my rebuilt SOS tranny and have a tranny forward section of tractor (tank, steering wheel, rad, etc). But I might just settle for a bell housing/PTO set up so it can at least start.
I don't want to do anything exotic like rebore to 4000 specs so I guess I'm asking, what can I do w/ the fuel system to get more HP out of it. (That's assuming someone didn't convert it over to 4000 specs by changing the crank & internals).

Okay, two part question:
1- Assume the engine is a 3000. With a rebuilt engine, what can the fuel system do to bump up HP. As I said, I'd like as much HP as safely (longevity & reliability) possible using 3000 parts AND it is a spare motor for the harvester (knock on wood), so it will be primarily PTO power needed.

2- assume the engine has be converted internally to 4000. The original 4000 was quite smaller then the 201 block 4630 I have now. What max HP can the 175 block put out, again, w/ the same specs.

I differ to the folks who have a lot more experience w/ Ford part compatibility. (Someone told me once that a 4000 injectors were the same as 3000 or would fit, or it was just pump adjustments....)

(Oh, for you out there, before the swap, I was tempted to put an industrial 201 engine in.... a turbo charged one, but I figured that's was over kill.....