Look at 1933 and 1936.


from Coachbuilt.com (707 used in Yellow Cab Co. bus - bought by GMC )

"Greyhound, the dominant U.S. intercity bus operator, arranged to sell its wholly owned bus manufacturing subsidiary C.H. Will Motors Corp. (see Will) to Yellow Coach during 1929, and Yellow subsequently designed and built a 250-inch-wheelbase Type Z parlor coach chassis to Greyhound specifications. This type of bus was the last con­ventional Yellow chassis to be introduced, as work was al. ready under way on new designs that enclosed the engine within the body. The big Z-250 used a 707-cubic-inch six­-cylinder engine, while smaller Yellows were equipped with either 616 or 568-cubic-inch motors. After 1930, GM Truck engines were used in the smallest models in place of the earlier Cadillac or Buick automobile engines.

Between 1931 and 1934, Yellow built and sold a small number of city transit buses with rear-mounted engines that drove forward. These were not particularly success­ful, the largest types encountering 'significant clutch trouble because the largest engine that could be accommodated within the bus was too small for the size of the ve­hicle. In the meantime the small types U and W were superseded by front-engine forward-control buses.

The use of letter designations was given up, and buses (and a few trolley-coaches) of the new designs were labeled with model numbers in the 700 series. Production of types V and Z, especially the parlor versions, continued until 1936."

Tim
1954Advance-Design.com
1954 3106 Carryall Suburban
1954 3104 5-window pickup w/Hydra-Matic
The 216 and early 235 engines are not "splash oilers" -- this is a splash oiler.