Sorry,

I did not see that the "A" is not a truck model in 1959 or 1960:

http://www.1954advance-design.com/chev-specs/1959-Chevrolet-c-ser.pdf
http://www.1954advance-design.com/chev-specs/1960-c-ser.pdf

Car 235 with 3-speed or 3-speed overdrive (it would have had hydraulic lifters).