From the link that Tim provided,
DCM was for the 4000 series trucks.

The 4000 series had a 216.
http://chevy.oldcarmanualproject.com/chevyresto/4677.htm

The 4000 series trans 4 speed,
is listed as conventional with gears type as Spur.
http://chevy.oldcarmanualproject.com/chevyresto/4689.htm

Maybe someone can explain spur verses helical gears.


-Tom

1950 Chevy 3100 w/ 1956 235