Rear end help - Impala Tech
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post #1 of 16 (permalink) Old 05-19-2013, 01:19 PM Thread Starter
 
 
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Rear end help

I have a 73 Caprice Convertible. What rear end is in here... I have no idea. I've found a ford 9 rear that should bolt right in. What's the width of the stock rear end and what's a good width to narrow it to to run a deep 26 inch wheel in the back. I also wanna use ford torrino bearings to install Baer disk brakes.
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post #2 of 16 (permalink) Old 05-19-2013, 02:12 PM
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You have a "Corporate" ten bolt rear end in your car now. It has an 8.5" ring gear and 28 spline axles just like the nine inch you are going to replace it with. There are a few exceptional nine inch rears that had 31 spline axles and shared the same nodular iron case that the GM ten bolt does, but they are rare and expensive since only high performance cars such as big block Mustangs were fitted with them.

A better choice is a twelve bolt rear end out of a 1970-'71 Impala. It will bolt right in, it is as strong as the nine inch and it doesn't suffer the four percent parasitic horsepower loss that the nine inch does. The nine inch has the pinion gear lower down near the bottom of the gear to engage more tooth area to spread out the force over more gear teeth (it is the basis for it's reputed strength). However by engaging more tooth area it increases the amount of friction which robs you of horsepower.

The only advantage the nine inch has over a twelve bolt is the press on bearings. Strange and Moser bot sell axle tube ends that weld onto a stock Chevy rear axle to replace the factory wheel bearings with Ford Torrino bearings. You can then bolt on any set of Ford, Chevy or aftermarket brakes you want. Since you have to buy new axles when you convert to Ford bearings you can buy the same 31 spline axles used in the Nine inch provided you buy your PosiTraction differential from Moser who makes the lager 31 spline side gears to fit in an Eaton PosiTrac rear end.

Big Dave
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post #3 of 16 (permalink) Old 05-19-2013, 02:14 PM
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Your rear end is likely a GM 8.2" ten bolt. The Ford 9" won't "bolt in". If you are capable of narrowing it, you'll have no problem doing the measurements needed, along with welding on the control arm mounts and spring perches. We can't answer your questions on width, you need to do your calculations based on the offset of your wheels. There's really no reason to swap in a 9" unless you are going to put down some serious HP, and running 26s, I doubt that will be a priority.

Two doors, four doors, wagons, and ragtops.
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post #4 of 16 (permalink) Old 05-19-2013, 02:16 PM
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I have never seen a Ford 9 inch just bolt in to any Chevy. Its going to require some work. A better choice would be a rear from a 94-96 Impala SS. They already have disc brakes and the right wheel bolt pattern. As for the 26 inch wheels, Good Luck.
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post #5 of 16 (permalink) Old 05-19-2013, 02:39 PM Thread Starter
 
 
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Thanks for the quick response... I just want to be able to run 600hp without worrying about the rear end failing me. Im not having much luck finding a rear end out of a 94-96 SS. I wish i had you guys knowledge and experience.
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post #6 of 16 (permalink) Old 05-19-2013, 03:31 PM
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post #7 of 16 (permalink) Old 05-19-2013, 04:26 PM
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Build that 600hp engine first, then worry about the rear end. And the transmission. And the driveshaft.

Two doors, four doors, wagons, and ragtops.
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post #8 of 16 (permalink) Old 05-19-2013, 04:32 PM Thread Starter
 
 
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Thanks Larry... Just got off the phone with the guy with the rear out of the 96SS, Will be picking it up tomorrow. What gear do you recommend? I have a 454 big block, 700r4 transmission, putting out between 500-600 hp on 26 inch wheels.
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post #9 of 16 (permalink) Old 05-19-2013, 05:57 PM
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I would use a 3.43, or a 3.73 ring and pinion gear as you do not need a lot of torque multiplication with a big block. Unless that 700R4 is really beefed up it will break like a dry twig the first time you get on it.

You also have to change your oil pan and oil pump pick up over to fit a car chassis as the truck oil pan will hit the cross-member and your steering linkage.

Big Dave
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post #10 of 16 (permalink) Old 05-20-2013, 04:34 PM
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I have a 200-4r and I chose 3.73 gears. After driving on it for a while, I think they are the perfect choice for an overdrive transmission. You have a .70 over drive, while I have a .67.

Nick


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post #11 of 16 (permalink) Old 05-31-2013, 06:10 PM Thread Starter
 
 
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hey guys whats required to put a 12 bolt out of a 69 impala in to a 73 caprice.
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post #12 of 16 (permalink) Old 05-31-2013, 06:53 PM
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I think you will have a problem. The 1965-70 Impala had parallel control arms with a Panhard bar to center the rear (shorter upper and longer bent lowers with the spring on the control arm as does the Chevelle). In 1971, and up through 1999 the rear end was held in place by a triangulated four bars suspension. This eliminated the Panhard bar but required the cast iron central case to mount the upper control arms on two cast in place mounting ears that are going to be missing on a 1969 rear end.

Big Dave
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post #13 of 16 (permalink) Old 06-01-2013, 12:12 AM Thread Starter
 
 
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ok thanks Dave
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post #14 of 16 (permalink) Old 06-14-2013, 10:26 PM Thread Starter
 
 
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What's the width of the b body chevy 71/76 rear end from axle flanges. And bolt pattern size. 5x5?
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post #15 of 16 (permalink) Old 06-15-2013, 11:08 AM
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Bolt pattern is 5x5. Width? Get out a tape measure and crawl under your car

Two doors, four doors, wagons, and ragtops.
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post #16 of 16 (permalink) Old 06-16-2013, 02:02 PM Thread Starter
 
 
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i would measure it but im 2000 miles away working. thanks anyways.
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