That particular one os from a 235 in a '55 2nd series truck, whcih is a bit longer than most others. If you look, you'll see the code "255" in it. They did that to differentiate the code from the 1st series engines, which simply have the "55" in the code number. There is a difference in the blocks, as the 1st series block in the high water pump full pressure block, same as '54, the 2nd series block has the low water pump.
BTW, mine decodes as a Tonawanda engine plant, 235 1/2 ton truck application w/3 speed.
