Identifying my engine

What makes you say the engine should be a 225? The "base" engine was a 170, with the 225 being optional.

Yes everything fits between the 170 and 225, except for the block, crank, connecting rods, and pushrods. Carburators will interchange, but the factory carb for the 170 standard shift was smaller the the 170 auto, and 225 stick and auto.