Q is also the plant location for Tonawanda
Q code in 1953 had RPO 313 = Automatic Transmission Option

available for
Two-Ten, Series 2100
BelAir, Series 2400

Your engine specs are listed here
http://chevy.oldcarmanualproject.com/chevyresto/53048.htm


-Tom

1950 Chevy 3100 w/ 1956 235