No go. The case is for a slant six only. Note the high location of the starter.
If interested, I have a 1965 727 small block tranny that would fit your 273 and work with your 1965 car's unique shift pattern (1 yr only for cable-shifts), sitting in my shed. You must hammer over the "pinch weld" at the fwd end of your tranny tunnel to fit a 727 (have read). I have not installed, so going by what the seller said, but from a Mopar show w/ knowledgable sellers. You can get 727 rebuild kits cheap on rockauto. I have a son in San Diego, so we drive there maybe once per year. PM if interested and can wait at least 6 months. I recall the parking cable cover is cracked (stupid mistake I made) and I'd have to pull it out and see what parts it has and condition.
