1965-1966 Shelby Mustang 9 Inch Rear End Housing

1965 and 1966 Shelby Mustang style 9″ rear end housings are very difficult to locate, but not impossible to duplicate.  With a little work, you will be able to duplicate this Shelby rear end housing, while saving a lot of money.  This guide will provide the basic steps and necessary parts to be able to complete this process.  In the end, you will be using a Ford Galaxie 9″ rear end housing center section and 1965 or 1966 Mustang 6 cylinder rear end housing axle tubes to duplicate a Shelby rear end.

Please note:  Other Ford 9″ rear end housings may have the same styling as 1963 and 1965 Ford Galaxies.  If so, you may want to try to use one of these if a Ford Galaxie is not available.

Parts Needed for a 1965 Shelby Mustang Style Rear End Housing

• 9″ rear end housing from a 1963 Ford Galaxie or any 9″ rear end housing that is flat on one side, rather than completely rounded with a small drain plug
• 6 cylinder rear end housing from a 1965 or 1966 Mustang

The shape of the center section on a 9″ rear end housing on a 1965 Shelby and “K” Code Mustang is flat on one side, rather than completely rounded.  This is why you will need a 9″ rear end housing with this characteristic.  The rear end housing on a 1965 Shelby used a smaller drain plug than the one found on a 1966 Mustang Shelby.

Parts Needed for a 1966 Shelby Mustang Style Rear End Housing

• 9″ Rear End Housing from a 1965 Ford Galaxie, or any 9″ rear end housing that is flat on one side, rather than completely rounded, with a large, flat, hexagon shaped drain plug
• 6 cylinder rear end housing from a 1965 or 1966 Mustang

The shape of the center section on a 9″ rear end housing on a 1966 Shelby and “K” Code Mustang is flat on one side, rather than completely rounded.  This is why you will need a 9″ rear end housing with this characteristic.  The rear end housing on a 1966 Shelby and “K” Code Mustang used a large, flat, hexagon shaped (6 sided) drain plug, approximately 1 1/2″ in diameter.

How to make a 1965 or 1966 Shelby Mustang 9 inch Rear End

1. Remove the axle tubes from the Ford Galaxie (donor car) rear end housing.
   Cut the Galaxie axle tubes flush with the weld at the edge of the center section of the housing, being careful to not damage the weld of the remaining tube in the center section.  There will still be about 2″ of tube remaining in the center section (the remaining tubes will be needed to guide and hold the 6 cylinder Mustang tubes in place, as discussed in Step 3).  Label the center section “Driver” and “Passenger” (the “Driver” axle tube is shorter and the “Passenger” axle tube is longer).
2. Remove the axle tubes from the 1965 or 1966 Mustang 6 cylinder rear end housing.
   Cut the Mustang axle tubes flush with the edges of the cast iron center section on the Mustang 6 cylinder rear end.  Deburr the freshly cut edges (grind the edges smooth) on the axle tubes for ease of fitting.
   Please note:  when these tubes are reinstalled, they will need further trimming to achieve proper length and center section offset (this is explained in Step 4).
3. Insert the 6 cylinder Mustang axle tubes into the Galaxie center section.
   Slide the 6 cylinder Mustang tubes into the remainder of the Galaxie tubes.  Push the tubes inward until the proper rear end housing width is achieved.  Remember to insert the tubes according to the “Driver” or “Passenger” label on the center section.   Once the tubes are  inserted to the proper overall width, use chalk to mark them at the center section weld.  Once chalk marked, remove the tubes.
4. Trim the Mustang axle tubes to the appropriate length.
   Measure the Galaxie center section from the location that the Galaxie axle tubes were cut to the inside end of the original Galaxie axle tube.  This measurement should be about 2″.  Using this measurement, add this amount to the chalk mark on the Mustang axle tube.  Now, cut the tube even at this newly measured point.  Repeat this process with the other axle tube.
   Please note:  the inside end of the Mustang axle tube should be even with the inside end of the remainder of the Galaxie axle tube.
5. Reassemble the rear end.
   Using a flat level surface, set the Galaxie center section down and firmly brace it.  Insert the Mustang axle tubes to the proper width, being certain that all of the components are braced so that they will not move.  Ensure that the components are absolutely straight.  Tack weld the Mustang axle tubes in place.  Double check that all tubes are straight before further welding.
6. Weld the Mustang axle tubes to the Galaxie center housing.
   If you are an experienced welder/fabricator and know that you can weld the tubes straight and securely, attempt to do so.  Otherwise, it is highly recommended that you take the components to an experienced welder/fabricator to perform this task.

Mustang Shelby and “K” Code drivetrain components are one of the most difficult to find.  Here is a way to duplicate your own drivetrain component.

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