door locks and trim clips- 1964 Dart

The link provided by Daliant is applicable only to '66-up lock cylinders. The '60-'65 cylinders are much more difficult to open and work with, and much more difficult to get parts for. If you're looking to buy new, that's a difficult and costly lock set to find these days. Occasionally they go by on eBay, or from one of the "usual suspects" in overpriced maybe-you'll-get-it, maybe-it'll-be-as-described NOS parts (such as the outfit in Georgia or the one in Washington). Interchange is '60-'65 A-body plus '62-'65 B-body.

Unless you're building a 100-point trailer queen, I'd simply enlarge the door lock holes and install the easy-to-buy, inexpensive, more-secure, easier-to-rekey '66-up door locks. They can be bought as a set of three (left and right door + ignition) all keyed alike.