This is a rear end axle conversion from 4 lugs to 5 lugs on a 1964 and up mustang 6 cylinder car. It involves removing the rear axle shafts and brake drums from the existing rear axle housing, sending them to me, www.coolcatz.com and I will precision machine into them a 5 bolt on 4 ½” pattern. There are no dangerous adapters or expensive, let alone labor intensive complete rear axle changes that may or may not work. This is a very easy “do-it- yourself” project. Simply secure your car on jack stands, take off the rear wheels, slide off the brake drum, unbolt 4- 9/16” bolts on the axle retainer, slide out the axles, box up the axles with brake drums and send to me. The machining process has a turn around time of about 3 days and costs $260.00 + shipping for both axles. Once you receive them back simply reverse the above process and bolt on your new 5 lug wheels! Please understand that the machine process is done on precision equipment and not a simple drill press, do not try this at home. We are a professional restoration shop in business for over 27 years and have done at least 50 sets so far and some are even used in drag racing with no strength issues whatsoever.