Your best shot may be to buy a complete diesel truck chassis and swap everything over to your frame. That way you get matching wheel lug pattern and the right rear ratio and maybe even the right transmission...might be way cheaper this way! You might even score a good set of rims and tires as well...
As a bonus you might find an air brake truck and get all the needed parts for that swap as well.
Don't over look school buses in you travels.
Mike B
