Attn Cobra3073: 8" or 9" Rears in our cars?

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Don65Stang

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I thought that all the 71-73's came with 9" rears. Maybe I'm misunderstanding what was said for the WFQ about this topic.

Doc and TwinturbomachI:

It should be noted that the vast majority of our mustangs had the 8" rear end from the factory. The 9" was generally found on the more performance-based (i.e., Boss, Mach I, CJ, etc) mustangs. However, the 9" carrier was used on many, many other full sized Ford, Lincoln and Mercury products and the carrier will bolt right up to our rearends. If you are building any kind of real power, you should think about changing to a 9" (if you currently have an 8").

Over the next week or so, I will develop a more in-depth tutorial on this subject to be placed in the "Data" section of the site.

GREAT responses Doc and TwinturbomachI!

BT
Is this info for the 71-73? My car originally had a 351-2v and it currently has an 8" rear. I thought that someone had put an 8" under it (for whatever reason) but the info above has me thinking it might be the original rear now. It's been opened up...axle tag is missing and there is gasket sealant ooze at the joint.

Thanks.

.

 
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OMS

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From what I have seen

All body styles

6 cyl and 302 cars had a 8 inch

351 2bbl, 351 4 bbl and 429 cars had 9 inch

Also every 4 speed car I have had, had an N case, some open, some posi

Don

 
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I will piggy back on what Don (OMS) and others have said or inferred, the majority of our cars actually came with the 8' carrier.

The 9' was USUALLY reserved for the larger (351C 4V and 429CJ/SCJ) or more performance oriented models. If you are want to be sure about the original equipment on your particular Mustang, you should probably order the "Marti Report."

BT

 

Don65Stang

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I will piggy back on what Don (OMS) and others have said or inferred, the majority of our cars actually came with the 8' carrier.

The 9' was USUALLY reserved for the larger (351C 4V and 429CJ/SCJ) or more performance oriented models. If you are want to be sure about the original equipment on your particular Mustang, you should probably order the "Marti Report."

BT
So if I have this straight, the 351-4V and larger equipped cars got the beefier suspension with the sway bar & staggered shocks and the 351-4V cars also were the first to get the 9". That statement is an assumption on my part based on what I've read and seen up to this point.

The 8" in my car is disheartening news. But since my 8" has been apart, maybe the PO will have at least put some smaller gears in there...I'll have to jack it up and count tire rotations.

BT, my Marti report is silent on the 8" vs 9" rear end size but does show a 2.75 open rear.

Marti%2071%20Mach%201%20351%202-V.jpg


 
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I believe you got most of it right.

Please understand that there are Mustangs and then there are performance-based Mustangs, like the Mach 1s and Bosses. The original WFQ was about Mustangs in general.

The 1971 Mach 1 came with the Competition Suspension as STANDARD equipment. I would think that your car should have come with the 9 inch rear, being that it is a Mach 1. Do you still have the staggered shocks? Are you sure that it has an 8 inch rear now?

BT

 

FastE

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From what I have seen

All body styles

6 cyl and 302 cars had a 8 inch

351 2bbl, 351 4 bbl and 429 cars had 9 inch

Also every 4 speed car I have had, had an N case, some open, some posi

Don
+1

 

Don65Stang

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I believe you got most of it right.

The 1971 Mach 1 came with the Competition Suspension as STANDARD equipment. I would think that your car should have come with the 9 inch rear, being that it is a Mach 1. Do you still have the staggered shocks? Are you sure that it has an 8 inch rear now?

BT
Thanks BT. It's a never ending thirst for truth and there is so much misinformation floating around on the internet it's hard to know what is correct.

I also thought that my car would have come with a 9". It is a 05 VIN and 63R body. It was a 351-2V originally but a previous owner pulled the 2V and installed a rebuild 4V. I'm 99% sure it is a 8" currently installed...oval shape, socket accessible bolt.

 

Tnfastbk

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I believe you got most of it right.

The 1971 Mach 1 came with the Competition Suspension as STANDARD equipment. I would think that your car should have come with the 9 inch rear, being that it is a Mach 1. Do you still have the staggered shocks? Are you sure that it has an 8 inch rear now?

BT
Thanks BT. It's a never ending thirst for truth and there is so much misinformation floating around on the internet it's hard to know what is correct.

I also thought that my car would have come with a 9". It is a 05 VIN and 63R body. It was a 351-2V originally but a previous owner pulled the 2V and installed a rebuild 4V. I'm 99% sure it is a 8" currently installed...oval shape, socket accessible bolt.
:worthlesswithoutpics:

 

Tnfastbk

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Roy: not until we see some Tusan trip pics. ;)
LOL that was a few years back, when it was not politically incorrect to do those things. So hopefully there are no pics. Sorry but would have to say there was a few 8 & 9 inch rearends there along with some really nice after market headlights.:p

 

OMS

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Don, your car 351C 2V would have has a 9 inch

I have had 60 or so 71-3's all 351 2 or 4 cars had 9 inch.

Don


Don, another possibility [ i hope not ] if the 8 inch looks original.

Have you pulled a fender to check the VIN

I have had several cars with titles and dash numbers that didn't match the shock tower numbers.

People have swapped dashes for better ones or color changes and they don't even think about that dash VIN number.

Don

 
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Don65Stang

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Don (Ohio), I've confirmed the vin, I'm good there. :)

Got any 9" rears? A 3.50:1 trac-lok would be a nice addition to my car. :D

 
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