Rear axle upgrade/swap

[naa10104]

Hello,

       I have a 73 convertible with a 351 C, 2V with a C6 auto and the original open rear end, conventional w/ 2.75 gears.  Drum brakes.  Curious is there an entire rear axle assembly out of another Ford product that would bolt right in ? Looking for disc brakes, higher gear ratio ... up to 3.55, and a limited slip/posi rear.  How high could I go on the gears without causing issues with the C6 and rpm's ?  No plans to significantly up the horsepower in the motor, maybe some light HP increases but nothing great.  Thanks for your help.

steve

 

[Don C]

The Ford Explorer has what you're looking for:

https://www.7173mustangs.com/thread-rear-end-suspension-and-wheels

 

[Bentworker]

What rear end do you have now? 8” or 9”?

 

[naa10104]

What rear end do you have now?  8” or 9”?

Pretty sure it is a 9".  Has the vertical bulge on side of the rear of the pumpkin.  If that helps.  Thanks

steve

 

[Bill73Ragtop]

Purchasing an already assembled 3.25 or 3.55 trac loc would work well. 3.25 is just right if you are doing combination of highway and local cruising.

Might want to consider getting a Detroit Tru-Trac which would also work well in either gearing. Tru-trac has the advantage of not having any clutches so you don't have any issues with clutch wear. If you do go with Tru-trac, make sure you use the right rear end gear lube -- it's kinda fussy with some oils and does not play well with some synthetic brands.

Either way its easier and probably cheaper than changing out the entire rear end.

 

[Ed Raver]

Purchasing an already assembled 3.25 or 3.55 trac loc would work well.   3.25 is just right if you are doing combination of highway and local cruising.

Might want to consider getting a Detroit Tru-Trac which would also work well in either gearing.   Tru-trac has the advantage of not having any clutches so you don't have any issues with clutch wear.   If you do go with Tru-trac, make sure you use the right rear end gear lube -- it's kinda fussy with some oils and does not play well with some synthetic brands.

Either way its easier and probably cheaper than changing out the entire rear end.

A 9 inch rear end from a 69 or 70 Mustang will bolt right in but you have to use 69 or 70 axles. This results in a narrowed rear end and you can then use a wider tire if desired. This gives you an extra 3/4" on each side.  3:25 is a good choice and a TruTrac is another good choice. I have done this to my 71 Convertible but I use a 3:55 with a C-6 and all is well.    Ed

 

[73pony]

I had the exact same rear in my '73 351 2v. I pulled the third member and sent it off to a place in Ames, IA. They installed 3.75 gears and a tru-trac (I am also running a 5 speed so could go more aggressive on the gears). Came back to me fully assembled, detailed and ready to pop back in. Price wasn't bad, under $1,000. Place is called Quick performance. A couple of other members recommended them to me and I was very happy and it was a quick turn around.

here is link to their page

http://www.quickperformance.com/

 

[Bentworker]

Purchasing an already assembled 3.25 or 3.55 trac loc would work well. 3.25 is just right if you are doing combination of highway and local cruising.

Might want to consider getting a Detroit Tru-Trac which would also work well in either gearing. Tru-trac has the advantage of not having any clutches so you don't have any issues with clutch wear. If you do go with Tru-trac, make sure you use the right rear end gear lube -- it's kinda fussy with some oils and does not play well with some synthetic brands.

Either way its easier and probably cheaper than changing out the entire rear end.

Pretty much what he said.

There are clutch type limited slip differentials, lockers, and torque biasing differentials like a Quaife or Detroit Tru-trac.

Every on has advantages and disadvantages. Personally I have a Tru-trac.

If you already have a 9” I’d stick with it.

You could setup new gears and differential yourself if you feel like a little project. You need a couple specialized tools and some time.

Other option is to pay someone to setup the gears in the third member.

As for brakes, there are a ton of small bearing ford 9” swap options. Mustang Steve is one. There is another that I can’t think of right now that actually has a drum in rotor hat parking brake setup. If I find it I’ll post the name.

 

[turtle5353]

If you can weld and fabricate some, the 8.8 swap is easy and cheap. I am still running mine with 0 issues.  The Explorer rear ends are cheap and plentiful at the local yards. Should be able to pick one up for $200 OR LESS.  You will need new u bolts, and driveshaft modified.  I had less than $500 in the entire swap, but I did everything myself except make the driveshaft. Local driveshaft shop did that for me. I got 3.73 gears, limited slip, disc brakes, and 31 spline axles in one shot. And everything in it is a Ford part, easy to get parts for at any local autoparts house.

 

[naa10104]

If you can weld and fabricate some, the 8.8 swap is easy and cheap. I am still running mine with 0 issues.  The Explorer rear ends are cheap and plentiful at the local yards. Should be able to pick one up for $200 OR LESS.  You will need new u bolts, and driveshaft modified.  I had less than $500 in the entire swap, but I did everything myself except make the driveshaft. Local driveshaft shop did that for me. I got 3.73 gears, limited slip, disc brakes, and 31 spline axles in one shot. And everything in it is a Ford part, easy to get parts for at any local autoparts house.

Thanks to all for the input !