It looks like you truck was most likely Transport Blue, a common optional color (Juniper Green was the standard color in 1954).
Here are locations of various engine codes. Most engines found the these trucks are not totally original (and almost all have been rebuilt). Yours is not the original color and does not seem to have 4 slits/vents in the valve cover (as used in 54/55 235 engines).
Nice truck.
One week after buying my 54 Suburban (in 1971), 5 of us went on a 1,000 round trip to Atlanta to see the Grateful Dead.
