Mopar #'s Matching

If you are not rebuilding stock why not look into recreating the dual 4-bbl option used on the special 275hp Darts that year, or mounting the later 340 6-pack setup.

As your dad's '64 never came out of the factory with the 318 you do have a precedent for an engine swap, but if you can get them to work it would be much cooler showing a built 273 than a swapped engine.