The 450 is like larger trucks that were speced for the purpose of the truck. Wheels could be stud piloted or open center Dayton. Brakes could be hydraulic, air over hydraulic or straight air. The original transmission would have been a 5 speed with several options available. The rear would probably be the same except the 54 a 6 volt electric and the 56 a 12 volt electric. The 5 speed would not have a cross member for the transmission. I don't know what an auto had. I 450 should have a double disc clutch. They probably used a single disc clutch to mate to the 4 speed. The frame would depend on the wheelbase. Both would have a 34" wide frame. The hoist and body would be whatever someone installed. The driveshaft would probably be different length and who knows what they used to put in a 4 speed. The springs would probably be the same.