WD-45 Engine Rebuild

I plan to use the tractor for pulling and bush hogging. The pulls we have around here (GA) use a transfer sled and you must operate in low gear only. I want to build for as much power and lugging ability as possible without making the tractor unusable / unreliable for occational bushhogging or without getting extremely expensive. I am leaning toward using AGCO pistons and sleeves for an AC 175 understanding that the ignition timing is critical with this setup. Is there a better choice for this application such as one of the 0.125 oversize options? Should I replace the magneto with a distributor? Pulled first time last week in the 4000# and 5000# classes coming in 4 out of 7 in both events. Ran out of traction in the first event and power in the second. Lost to a JD B and WD-40 in both events. Beat an H Farmall, Ford 601, MM, and MF135 between the two pulls with an engine that is burning, leaking, and blowing oil. I have a couple Farmalls but I'm impressed with this Allis.

Any help is appreciated. Thanks - Franklin

As I see it, I would recommend that you perhaps look at wider tires, and work at using that tractor in the various weight divisions. Wider tires and more weight might give you more bite. I dunno - just my observation.