Look into scarebird brakes and research theirs as you need to change master cylinder proportioning valve lines and if you want you have you will be able to use most existing wheels by using a disc brake and rotor hardware you need to make fit,Most wilwood or classic require larger wheels to accommodate caliper size.If you were lucky to be 1971 or newer most chrysler had larger bolt pattern or can accomodate more easily as wheels were 5x4.5 as opposed to 5x4 inches as many earlier models .Your model axle package will affect your decision.I also have drum on 1970 duster and believe i will go with scarebird as it will let me keep rally 14 inch and perhaps is easier to find parts to complete conversion.If you need more read on here and moparts as your model wheels and availability of junkyard parts affect choice,