John H. - I did call Patricks; his 3.55 and 3.38 kits are for 1940 and later. Apparently theres not much you can do with a '39.
HiTork - Are you saying you used the axles out of a 54 truck in a 48 passenger? I imagine the axles would have to be shortened. I would also like to stay with the 6 lugs. I'm a little confused on your application.