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Discussion Starter · #1 ·
Has anyone had the same question as I believe the limited slip is better in a f body than in a caprice but with the rearend out of an f body bolt in a b body I have a caprice (96) and instead of changin gears and all that can I just bolt a higher geared f body rear end with disks right into my b body ?
 

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f-body rear is narower than a b-body rear i would look for a impala ss rear it a 8.5 ring gear and 30 spline axels so they can be built almost bullit proof for little money
 

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if the caprice came with a posi which im not shure if it did they would probably be the same all my frends ss came with auburns that broke and they put eatons in there place
 

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Discussion Starter · #5 ·
I have a 96 caprice it lights them both every time as long as im straight it just won't stick if im at any kind of an angle but if I start straight then kick it out it will go forever I just was wonderin if the impalla rear was a lil more agressive and I just wanted to hit it all at once with gears disks and a better posi all in one shot by just bolting in a better rear end
 

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i dont think that your caprice has a posi in it. jack the car up from the rear spin one wheel if the other wheel spins in the same direction its a posi if it spins opposite its a open rear. we used to do that backing up to do a two wheel burn out with open rear corollas back in the day
 

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Discussion Starter · #7 ·
Yea I know that about rear ends I build 9ins all day long the caprice is equiped with a limited slip rearend factory I need to know if the ss is any diff and if anyone has the info or codings that I can go by to differinciate the 2 internals apart and in what ways they are diff
 

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The Impala SS rear end was nothing special. All the 91-96 B-body's used the same Auburn Cone clutch differential. The Auburns are hit or miss with how long they last, before the clutches wear out, and it acts like an open diff. They typically last from about 100k to 200k, before they fail to pass the factory test procedure. The procedure, is just putting one tire in the air, with the car in Neutral, and then attempting to spin the wheel with a torque wrench on the lug nut. I forget what the amount of torque is, but I think it should be better than 70 lbs/ft.

I'm not sold on the Eaton 400# being stronger. I have one in my Roadmaster with about 30k on it, and countless drag strip passes. When you put the tires in the air, in park, you can grab a tire by hand, and spin it. There is a little resistance, but honestly not that much. It did pass the factory test. But sadly, the 90k Auburn in my other 95 Roadmaster, took more effort to spin, and took more torque before it unloaded. I thought about that Eaton was just getting worn, so I checked my 96 9C1, which has made 3k on it's Eaton. Same thing.

A friend of mine, has nearly 200k on his stock eaton, and has been abused at the dragstrip, many times, behind a Hot Cam 350, and then later a Comp Cams 503, 383, with ported heads. It still passes the factory test.

The 90k one in my 95 Roadmaster, seems in certain situations. In the same situations, the 150k one in my 96 Civi Caprice, feels less worn out. One of my 94 9C1's, the tires will spin opposite directions with virtually no force, just like an open diff will. yet when you have it on the ground, and punch it, the thing always smokes both tires. This one has well over 200k, but I'm not sure how much, since it has had a few different clusters, since it's orginal went out just after 200k.

If you build Ford 9" axles "all day", I can't believe you don't know this. The F-body used the 7.5" ring gear 10 bolt, and the B-body's that had a positraction, used the 8.5" ring gear 10 bolt. They did put the 7.5" 10 bolt in Caprices. They were normally found in civi cars, behind the 305 in 91-93, and the 4.3 in 94-96. Stock LT1 power will destroy one with positraction, in short order. That axle just handle the stress from all the extra weight of a Caprice. There was an ISSF member, that blew his 7.5" up about 3 times, behind stock LT1 power, in his Caprice. Then he got smart, and pulled an 8.5" rear from the junkyard.
 

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Discussion Starter · #9 ·
Yea I knew the tire spin off the ground is never a deff way to check for posi ..... yea mine is the same way u hit it on the pavement and they both go up in fire I just want a lil more aggresive bite than it has mine just turned over 160k just changed the opti from factory it was owned by an older person that didn't really take care of it so I am bringin it back to life so what I am dealing with is pretty much just the way they are and even the aftermarkets not much better .....?
 

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Use a period every now and then, damn it. It goes a long way.

There is the Detroit TruTrac, which is a worm gear style. I have seriously considered a Detroit Locker for my Roadmaster. But the biggest thing keeping me from doing one, is the high cost of one. In the 4wd world, they are nearly indestructible, and are the gold standard for locked axle performance, that still can automatically unlock.

Another posi you might have come across, that would be a very bad option, is the Eaton Gov lock, in the GM truck 8.5" axles. They are called the gov bomb, for good reason.
 

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Impala ss rears where a tad wider than the civis,
 

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You are thinking of the SS/93-96 Civi Caprice Sedan 8.5" axle being 1598mm vs the 1550mm(ish, forget the exact) 9C1 / 91-92 Civi sedan / RMS / Fleetwood 8.5" axle.
 

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anyone know where the 1a2 rear fits in to the rest? well it was swapped for a non 1a4 rear from a caprice wagon, everything appeared identical (width)

I would like to eventually put in some 3.09 or 3.23 ish gears to replace the 2.56's, and dont know if I should just get a 12 bolt and do the fab work to mount it up (have access to a plasma table, brake press, welders, mills, lathes... I could do the work to shorten down the axle tubes if need be, put on all the brackets...

would it be wise to just go straight to a 12 bolt, or re-gear a stock 10? if I ever win the lotto or somehow come into enough money, the wagon will get a big displacement LT1 with some sort of forced induction.
 
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