As mentioned, the hood emblem on a 55.2 has a short wing at the top of the emblem and the 56 has a long wing at the bottom.
The 56 and 57 hood emblems are the same casting, but they reversed the bow tie and background colors...56 has a red bow tie with black background and 57 has a black bow tie with red background.
The 55.2/56 fender spears look the same, but the 55.2 is one piece with 3 mounting studs and the 56 is two piece (series numbers are separate from CHEVROLET) with 4 mounting studs.
Apache, Viking and Spartan as well as the Fleetside nick names didn't start until 1958, which was also the beginning of the dual headlights.
Mike B
