Distributors and Ignition Components

The photo above shows the Autolite vacuum advance units side-by-side. The wider band advance on the left ( 11/16″) is a 4 speed unit. The thinner band advance on the right (9/16″) is a C6 unit. Note that in ’71, the vacuum advances changed to a “cast-in” front nipple instead of pressed or screwed in steel front nipple like previous years. Both units have this “cast-in” front nipple that was used from July ’70 through ’71.

Although not evident in our side-by-side photo above, the wide band (11/16″) for Manual Transmissions is the gold CAD plated. The narrow 9/16″ ban for Automatic Transmissions is silver CAD plated.

These photos show the difference in the end plug for the front chamber of the dual advance unit on the distributor. The 67 – 70 vacuum advances used a steel plug (right, in above photos) whereas the 71 switched to an Aluminum plug.

The picture at left is a side by side comparison of a PVS (Ported Vacuum Switch) and an EPVS (Electric Ported Vacuum Switch). These switches mount on the thermostat housing and provide vacuum control to the distributor based on coolant temperature. Some 429 CJ and SCJ engines have the EPVS (close-up center) while most others have a 2 or 3 port “vacuum only” PVS control valve (3 port version shown at right). Research is currently ongoing to understand the purpose of the electric feature on this valve and why it was used on only some 429 CJ/SCJ engines. This information will be updated when we reach some conclusions. Two views of the special wiring harness used for the EPVS are shown below.

The picture at left is a side by side comparison of a PVS (Ported Vacuum Switch) and an EPVS (Electric Ported Vacuum Switch). These switches mount on the thermostat housing and provide vacuum control to the distributor based on coolant temperature. Some 429 CJ and SCJ engines have the EPVS (close-up center) while most others have a 2 or 3 port “vacuum only” PVS control valve (3 port version shown at right). Research is currently ongoing to understand the purpose of the electric feature on this valve and why it was used on only some 429 CJ/SCJ engines. This information will be updated when we reach some conclusions. Two views of the special wiring harness used for the EPVS are shown below.

This is an original 12 volt Autolite Yellow Top Coil as was used originally on the 71 Mustang/Cougar (and most other Ford products of that timeframe). It carries part number FAC-12029-A. If you are using an aftermarket high performance coil, you can simulate the appearance of the original by using yellow Testors model paint on the coil cap. A decal with the Autolite logo and part number is available from most Mustang parts houses.

Rev limiters were installed from the factory only on 4 speed cars and were mounted to the passenger side shock tower as shown in the two photos below. A wiring diagram for the Rev Limiter is shown below right:

Application Information for 429 CJ/SCJ

(Note: “F” is for “F Body” – which is Mustang/Cougar. “B” is for “B Body” – Torino/Montego)

As can be seen from the MPC (Ford Master Parts Catalog) above, there is some confusion about which limiter is used on the 429 SCJ. The MPC shows BOTH the D0ZF-A and -B. Examination of an all original 429 SCJ Mach 1 reveals that it was equipped with the D0ZF-B with the 6150 RPM limit. The CJ is shown to use the D0ZF-A with the 5800 RPM limit.

Rev Limiter Ink Stamping

The ink stamping found on an original 429 SCJ Mustang Rev Limiter contained the following information:

AUTOLITE 7046
ENG GOV 6150 RPM
DOZF-12450-B

Robert Myhrer’s two 429 Mustangs enroute to the Silver Springs, Florida Car Show on 1/11/02.