From what's pictured, I can tell you that the serial number tag is from a 54-55 engine. The 53 and earlier tags had Supersonic (rather than 226) on them. Does the engine have the supercharger lower pulley on it? They're easy to spot as they have a large groove to accept the supercharger belt, as well as a narrower one to accept the water pump/generator belt. If so, someone may have removed the supercharger and associated equipment and subbed in parts from another engine.
Another item to check would be the distributor. Supercharged engines used a Delco 1110237 unit while non-supercharged 53 and 54 cars used a 1110224.
In 1954, 226 tagged engines were used in the late Specials as well as in the Manhattans. The difference of course was the former did not have a supercharger as standard equipment while the latter did.