273 Engine year Car 1967 Plymouth Barracuda

And with block stamped 1-20-67 that would mean the block is a 67 I guess
Anything cast and stamped in Jan will be that year. That is 5 months into the production year. Mid year. Now, never say never. Now, it is posible for a block to be cast and not assembled until a few months later or assembled and not installed for a few months but that has rarely happened that I have heard.