Vin on the engine vin is "0769813 F55Y", casting number is 3836233. Head is a 3836850 dated C 1 2. It's in my '54 so it's not a marrage from the factory. Given the multitude of paint colors I'd think it was a rebuilt at one time. Lifters appear to be solid, no spring deflection when I pish down on them. Might have been a purpose built rebuild, I don't know.