In addition to the 1970 kit described in another post, I've now got all the parts needed for a rebuild kit for the brake pressure differential and control valve used on several 1967, 1968, and 1969 Ford and Lincoln-Mercury vehicles (Mustangs included!) equipped with front disk brakes. Cost is $25 plus shipping. Here's a link to see the details and place an order:
http://musclecarresearch.com/shop/index.php?main_page=product_info&cPath=4&products_id=28