June 1, 2005

We have indeed covered this subject many times before, but we'll hit the highlights again. The V-8 spindles from most Ford intermediate vehicles are interchangeable as long as they are used with the corresponding wheel bearings and outer tie-rod ends. Two styles of disc brake assemblies can be used: either the four-piston, fixed-caliper style from 1965-1967 or the single-piston, floating-caliper style from 1968 and later. Early fixed calipers utilize a bracket to mount the caliper to the spindle, therefore the spindle can be from either a disc-brake or drum-brake vehicle. Later floating calipers fasten to the spindle directly, thus disc-brake spindles are unique to a disc-brake car.

Your choice of disc-brake styles will obviously dictate the spindle choice. The early four-piston setup is correct for your car. However, they cost more and used parts are not readily available. The newer style single-piston setup is more common as it was also used into the '80s on Granadas, so a donor car can usually be located fairly easily. If you still have the '69 Cougar, its brakes will bolt into your convertible with the '69 tie-rod ends.

A dual master cylinder from a '67 and newer Mustang will fit your early car with a bit of fabricated plumbing. A proportioning valve for the rear brakes must also be plumbed in.

Boss Headers In A '66I have a '66 Shelby GT350 with a Boss 302 engine and I'm trying to locate someone who makes headers for that application. Any help would be appreciated.Brad PippettVia the Internet

A set of headers for a '69-'70 Boss 302 Mustang will fit your combination. However, the tube for the No. 2 cylinder will require some slight modification because the tube interferes with the shock tower. It should be cut and rewelded to provide clearance.

Another choice is a set of specialty headers designed to install a 351 Cleveland engine into a '65-'66 chassis. As you know, Boss 302 heads are almost identical to 351 Cleveland four-barrel heads, so those headers will bolt up to the Boss engine. A small interference may occur because the Cleveland is a little taller and wider than a Boss 302. However, it can be done. Call Mustangs Unlimited at 888/398-9898 for a set of its conversion headers.

Not-So-Cool JerkI own a '72 Mustang hardtop with a 302/automatic. For some time while driving between 25 and 55 mph, I get a jerking, holding-back sensation. I performed a complete tune-up (points, condenser, cap, rotor, plug wires, PCV valve, and air filter) and even switched to a PerTronix ignition system. The problem is still there. The car accelerates just great, and runs fine otherwise. It only exhibits the problem at a steady speed. What else should I check?Andy KobackVia the Internet

The condition you describe is a classic case of "lean surge" and is related to a problem in the carburetor. The problem is in the intermediate circuit and is creating an improper air/fuel mixture under light throttle conditions. A carburetor is a combination of idle circuit, intermediate circuit, and power circuit as it must provide the correct air/fuel mixture under all those driving conditions. As you can imagine, the carburetor must blend the circuits together continuously, depending upon engine load, for seamless operation. It doesn't take much to upset the carb and only a small amount of debris or varnish deposit from old gasoline can partially clog a circuit. Rebuild or replace your carburetor and your problem should be solved.