9” Rear End Housing Identification

Does anyone know what car this rear end housing would be out of by the measurements.It is 54 3/8” from outside to outside of the flanges.It is 43 1/4” from center to center of the spring perches.Where it tapers down the smaller part of the tube is 2 3/4” in diameter.The nodular center section has 3.91 gears and is a Traction Lok.I dont know if the housing and center section are original to each other.Thanks for any help.

The housing measurements you give are pretty much the same for a 71-73 Cougar rear.

Randy Goodling
CCOA #95

The center section case has a casting date. The center section pinion bearing hosing also has a casting date. Both also have casting ID numbers. If you posted photos of those it would make identification possible. The ring gear has a casting ID number too. Again not possible to id something based on no information.

The housing pictured looks to be from a Torino / Cyclone / Mustang / Cougar based on the tapered ends.

BTW 1967 - 70 Mustang / Cougar / Comet / Fairlane axles are 67-70 Mustang 59.25 inches from axle flange to axle flange. Subtract 5" to get the measurement for the bare housing. Based on that your measurement seems to indicate 1967 - 70 Mustang / Cougar / Fairlane / Comet if we guess that you are off by 1/8". Photos of the top of the housing and the rear of the housing might make it possible to narrow the date range.

I dont have access to the center section at this point.When I decoded the tag it showed it was a 3.91 Traction Lok and from either a 1969 Cougar or Mustang.The casting numbers on the center section are all 1969.I believe the 3.91 gear ratio was only available on a car with a 428 SCJ engine or possibly a Boss 429.I do not know if these are the correct axle housing measurements for a 1969 Cougar or Mustang.The gentleman who owned this housing and center section had two Boss 429’s and a 1969 R Code Cougar.A lot of his cars were disassembled so this is what I am trying to determine with the info I have.

If it is between 1967 and 1970 it is the right width. Let’s see - is 1969 between 1967 and 1970? Holy crap it is!

I think you could special order a 3.91 in anything but yes there were more 428 / 429 Boss / 302 Boss cars equipped that way. Without photos of the third member and the tag no telling what it is worth to the right guy. Also need to know if any of it is good or if it is shot.

If someone special ordered the car they could have what ever was available. What if the info off the tag? That’s the big one. It could be from a Fairlane/Torino Cobra.

Tag data would be the same from any of those cars because the entire rear axle assembly would be the same as Mustang / Cougar.

Gee that’s funny, my Ford Parts Interchange Book, lists different Suffix codes for Torino/Fairlane and Mustangs. Springs seat center is different width, making it a different part number. Center section and axles the same, but housing is different. What’s the 3 letter code in the top left corner?

I did not know the spring perches were set differently.

They are due to fender and frame limitations. Interestingly enough, it also shows 8" and 9" using the same 28 spline axles on a lot of vehicles. Length, bearings etc. I do believe a 68-69 Torino/Fairlane, but the 70/71 Had a big make over. just as 71-73 was a big make over.

Here are a couple more pics.

No fill plug on the back so no earlier than 1968.

Two holes drilled in the top so no earlier than January 1968.

It’s a typical mid - 1968 model year to 1970 9" rear axle housing for Mustang / Cougar.

Thanks for the info.I will post a pic of the tag when I get a chance.

Does the fact that there are 2 holes in the spring perches make it a Cougar vs. a regular Mustang? The second hole was for alignment of the pinion wedge which Mustangs did not have.

The Mustang used the same housing.

I asked because I had to replace the original perches with some brutish monsters from Moroso. Upon reassembly, I noticed the need for the second hole. Out came the drill press. Now all is well.

No idea on Moroso perches. The ones that Ford installed fit both Mustang and Cougar.

The Perches had to be replaced because the PO had neglected to secure the leaf-spring U-bolts and ended up rounding off the original perches. Additionally, the U-bolts had worn grooves into the top of the differential housing so deeply that you could almost see gear lube through them. The Moroso perches are much, much heavier and more substantial the the Ford version. Summit Racing had them listed under “leaf spring perches” with various axle housing sizes and spring width options.

I thought the two holes started in '70, with the '69’s having just one hole and using a bolt with a vent to serve double duty as the axle vent and hold down for the brake line block.

Chopaka, you can try looking for a 2-digit hand stamped date code on the front of the passenger side of the housing, located just to the inside of where the axle flares out. Unfortunately, it won’t tell you a year but it will give you a month and week of that month. That might help you narrow down what car it could go with.