If you do not need to keep your smog reduction equipment, you can replace the feedback BBD carb with a non-feedback BBD carb from an earlier AMC. Many think that the Motorcraft 2100 or 2150 is a better replacement carb. They are a two barrel carb from many Ford and Mercury engines. There are different sizes of Motorcraft carbs, the ones that are the proper size for the 258 have 1.08 cast into the body of the carb. You will also need a base adapter to bolt the carb on and linkage for the throttle, along with air cleaner.