George, you bombed this one.

4430 is nothing like a 4520.....more like a 4320 or 4020. 4520 grew up to be a 4630, lots heavier tractor.

4430 generally had 86mm axles but could have 92mm also.

Lots of 4430's had 8 bolt front hubs, probably half and half on the ones around here. Spindles are the same whether 8 or 6 bolt. We kept the 8 bolt hubs from the 44 we sold years ago and swapped them onto the one we bought new which will be here until the end.

4430s used at least three different injectors over their production run. Not sure that any were better or worse, but ours have never been out of the head at 8000 hours and what, 30 years now. Pump has never been off, either. There were multiple choices for the pump also. Earlier ones have the mechanical linkage for the overfuel at starting button which can make them start hard if not well adjusted. Later ones are like the 40 series (operated by oil pressure, I think, right Bob or Ron?) and pretty well trouble free.