Technical Ford 9” help

So I need a little help I purchased a Ford 9 inch or what I believe to be a ford 9 inch. I dropped it off at the mechanic to get rebuilt and he said that I have a Ford 9 1/2 inch and that they’re no good. What are the thoughts on the ford 9 1/2 inch to be used on 1931 Ford coupe. Are parts available for that if needed. Please let me know your thoughts on this.


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From Kevin's stang page

 

Yeah I saw that article as well. Just wondering if anybody here has actually used this rear end in any projects


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I think an actual 9" pumpkin will slide in the 9 3/8" housing. Good luck finding 9 3/8" gears. Just find a 9 inch pumpkin.

 

I'm pretty sure at some point I had a mid 70's t-bird rear that was 9 3/8's and I did slip a regular 9 inch center into it.

 

Whether or not it will work for you, depends on what you want to do with it.

We don't have nearly enough info from you, to help you decide.

 

Chances are that if it did come out of a mid 70's land cruiser, is too wide for a '31 coupe. Narrowing jig, shaving existing brackets off mounting ladder bar(or whatever) brackets would be a start. '57 ford or '66 bronco are a nice width for 32-34 Fords. Might work for model A.

 

It came out of a 71 ford f-100 and it’s perfect length 61”


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but what do you want the machine shop to do with the thing?

 

Maybe perfect for a f100 truck. 56-57" wheel mounting to wheel mounting would be better.

 

I already mocked it up and it fits perfect


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That is supposed to be mechanic buy auto correct struck again


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It’s more like the rearend mechanic.. but anyway, if I can just drop in a 9” housing I’m cool with that


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9-3/8ths rear were big car..I had one that came in a 67 state police cruiser..3.00 gear, 4 pinion open diff, 31 spline axles, big bearing and big brakes..Not sure about when/if they were in trucks but would definitely handle a 1/2 ton pick up; even the big station wagons had a pretty high load capacity..9" chuck will fit 9-3/8 housing; visa-versa if housing is notched by 3/16 two places at mounting flange for ring gear clearance; in some cases ring gear may hit back of housing..So if a 3.00 gear is ok..

 

What type of spring perches are on the existing housing, and what type of suspension are you planning to use?

 

… If you're going racing. When theses first appeared around 1970, some Pro Stock racers tried them (bigger is better, right?) and broke the non-nodular-iron cases. Some of the mods done to the case casting to allow the larger gears to fit weakened it too much for that duty. So if you don't have big power, sticky tires, and the need to dump the clutch, it'll do fine....

 

Not racing.. motor is a 1955 hemi 270 not much power maybe 150 hp..


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All true Seb but in the (my) hot rod world view the weight load issue isn't the big issue, it's the strength of all the related third member components as well as axle strength.
Most of the oem housings themselves are pretty capable pieces, at least the bigger/later ones, even in stock, untouched condition those are a pretty beefy piece, short of high horsepower applications
I can't answer for everyone but I learned a long time ago to not even muddy the picture with stock axles especially if any soft tire compounds are brought into the picture.

 

Will it work? Yes, and if you want to step up later, the 9" has the same mounting pattern and will go in your housing with matching splines.
It'll spin (with one leg), so yes it'll work.

 

Ford 31 spline 9 3/8 rears began appearing in 1966, I believe, standard equipment in Lincolns, and in FoMoCo products that were delivered with 428 ci engines. They were in cars through '75, and Econolines through '76. The 31 spline axles in these are a bit shorter, so you may want to check length if changing axles. Some say it's not an issue, and some do.

 

Ok so I’m your opinions it should be an ok rearend to use?


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it should work. You might want to go to rockauto.com or something similar, to see if you can find all the typical replacement parts you need for it--brake parts, wheel bearings, seals, gaskets, etc. My guess is that you will be ok.

 

Awesome thank you...


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It's going to look awfully big and will be very heavy for a 31 coupe.

 

Yes it will be ok to use, just ok doesn't set the bar very high but then again we don't have a full grasp of your plans.
In my way of thinking there are other "just ok" rearends out there and they will have better aftermarket support down the road, compared to the 9&3/8" unit.
I don't recall the interchange regarding u-joints but if you do put a 9 inch in the bigger housing and have your initial driveshaft built you may at a minimum need to use a hybrid u-joint or even need the driveshaft modified again. Might as well put that money into the right rearend to begin with.

 

Maybe find out from your mechanic exactly what he finds "no good" about it.

 

If you are going to rebuild it, I would go with a standard 9 inch center section. It will fit in a 9 3/8" housing with no problems. You will need to get the axle length correct, but if you are going to narrow it, you will have to address that anyway.

 

9 3/8" housing features these notches for larger ring gear. A 9" centre I believe is a direct bolt in, just make sure it has the correct 31 spline count as yours.

 

I have 2 9 3/8th rear ends, one out of a 1971 429 LTD wagon, and one out of a 1976 460 LTD wagon. I am going to strip the hardware off the 1971 rear end, narrow it, and use a 9 inch center section. Both my rear ends are equipped with 31 spline axles.
Brake parts are no problem. I checked with my friend that is in the auto parts business, and he states that he can get anything I need.
The 9 3/8ths center sections are just fine for the street, but there isn't much of a selection for gears. Mine both have 2.8:1 ratios, and I want to run a minimum of 3.56:1, and more preferably a 3.73:1 in my truck (behind a warm 454 bb Chev). I know there are 3.5:1 9 3/8 center sections available, and if I can find one, I'll happily use it.
Bob

 

Cool thank you guys


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