Fox Ford 9 inch, can it be on the cheap side?

ndfox92

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Nov 23, 2020

#1

• Nov 23, 2020

• #1

wondering input on ford 9 inch rear diffs. 92 mustang, current setup is ford 8.8 with yukon axles swarr bar and 3.27 rear. factory diff. brakes are cobra rear disc using an adapter plate, strange /UPR coilovers and MM lower arms with whiteline uppers. the plan was to do rubber bushing uppers and a panhard bar and then call it a day. but then a built motor happened. looking to upgrade the rear but in a somewhat economical way...i want to go 9 inch but is there a way to retain the cobra rear disc setup? can a rear diff be found at a junkyard? id rather find something than buy the housing that someone painted and is selling online. the front carrier seems to be the most expensive part. whats the best(but on the cheaper side) way to do this?

 

90sickfox

Wasn't a pretty sight...and I've got big hands

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#2

• Nov 23, 2020

• #2

You can luck up and find a 9 inch in an old Ford truck or motorhome. The housing will still need to be shortened, leaf spring mounts cut off, the center section may need hybrid u joints to mount to the driveshaft.



The cheapest quickest option would be to buy one new, complete with axles and brake caliper brackets.



The 11.65 brake conversion is available from 200 to about 400 bucks. Takes the guesswork and time out. Think about crawling around trying to find some junkyard rear thats not a rusty mess inside. Then you've got to find someone with a jig to properly cut and weld it....then you still need to order axles, bearings, gears, etc. and hope it all works out. If one measurement is off you are screwed.

 

KRUISR

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Nov 24, 2020

#3

• Nov 24, 2020

• #3

ndfox92 said:

but then a built motor happened.

Click to expand...

What kind of a motor build happened that the 8.8 is not up to snuff? Motor capabilities before and after build?

 

ndfox92

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Nov 24, 2020

#4

• Nov 24, 2020

• #4

appreciate the feedback! and it went from a 306 that had low compression to a bored out 351 based Dart 454, so a little bit of a jump i guess.

 

KRUISR

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#5

• Nov 24, 2020

• #5

Purpose of the car? Hard launching drag car? Embarrass unsuspecting foe on the street? Road racing? Autocross?

 

ndfox92

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Nov 24, 2020

#6

• Nov 24, 2020

• #6

unsuspecting? absolutely. haha, but the idea in mind has always been autocross. I figure the hard strip launches is what would kill the rear anyways. I just don't see it cost efficient where if say the rear diff breaks or an axle goes, to replace it with a bigger spline diff and axles. money wise id probably be close to a basic 9 inch. I don't even have c-clip eliminators and that's been a worry also. I know strange made a 8.8 eliminator kit to work with the cobra brakes but I've never looked into it.

 

KRUISR

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#7

• Nov 24, 2020

• #7

If the concern is about a bracket to mount the Cobra brakes, any bracket can be made. It is really not that hard if you can do some basic fabrication. Can you measure, cut, weld material in the 1/4" to 3/8" range? If so, you can build a caliper bracket for any brakes you want.

Are you staying NA? So looking for what power level?

 

ndfox92

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Nov 24, 2020

#8

• Nov 24, 2020

• #8

very true. i guess i just like the whole idea of using parts from different cars to make it work. i have ATS brembos up front. the parking brake works in the rear like it should also. yeah staying NA. its a fresh build so it runs but still breaking it in nicely. id assume on the dyno it would make 600, give or take.

 

KRUISR

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#9

• Nov 24, 2020

• #9

What is the spline count on your current yukon's? Don't forget the issue with c-clips is IF the axle breaks you have a loose wheel. The c-clip is not the strength part of your rear end. I would think a good aftermarket 31 spline axle (even with c-clips) will be fine for what you are wanting to do.

 

ndfox92

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Nov 24, 2020

#10

• Nov 24, 2020

• #10

28. oh alright then, if and when ill look into going 31. thank you again. answered my questions.

 

2000xp8

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#11

• Nov 24, 2020

• #11

600rwhp is nothing these days.
IMO, it would be a waste of a lot of time and money, unless you are narrowing your rear (which causes all kinds of other issues).

 

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