Well, if I was a betting man, I would bet large sums of money that the 3/4 ton king pin is wider than the 1/2 ton king pin. that being said, it would not be practical to bore out the eye of the 1/2 ton axle, because you would be begging for failure. You may be able to have the 1/2 ton kingpins bushed to fit the 3/4 ton spindles. Of course I don't know off hand the actual dimensions of either kingpins or spindles. Are the king pins for 1/2 and 3/4 tons the same height?
John
