Let's cut right to the chase. Disc brakes simply work better than drums. If you have a classic Ford with drum brakes and drive it once a month to the local cruise night, you might want to turn the page. However, if you have some decent power under the hood and like your car to stop as well as it goes, then disc brakes are going to be part of your upgrade plan. A weekend in the garage upgrading the front drums to a set of discs with new calipers and hardware will really make a difference. While that difference is certainly measurable, even by the seat of your pants, you can make it even better by ditching the rear drums and going four-wheel-disc on your ride.
Adding a rear disc brake kit can not only reduce your braking distances, but it can also make for a total brake package that reduces reaction time from the brake pedal to the rotor (drum brakes require a larger gap between the brake shoe and drum, resulting in more pedal movement before brake application). Furthermore, many owners dislike the "disc/drum" combination behind their fancy aftermarket wheels. You've paid good money for those nice aluminum 18-inch five spokes, why have some blacked out or body-color brake drum sitting behind it when you can have a shiny brake disc that tells the world your classic Ford muscle can stop just like a new car.
The biggest problem with upgrading to rear discs is the cost. For many, the cost of a rear disc upgrade just about mirrors the cost of the front disc upgrade they've already installed, and while the rear disc setup does help, it is not as big an improvement as upgrading the front drums to disc, as the front performs the majority of the braking needs. In the end, the owner feels cheated for spending big-bucks on the rear disc to not "see" the same improvement as when they installed their front disc conversion. All is not lost, however, as the folks at CJ's Pony Parts have partnered with the brake hardware experts at The Right Stuff Detailing to offer a rear disc brake conversion that will fit most early Ford rears at a jaw dropping price!