Corporate 10 bolt rear end - Impala Tech
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post #1 of 9 (permalink) Old 04-29-2007, 12:08 PM Thread Starter
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Cool Corporate 10 bolt rear end

If you have a 1965-1976 Impala with a 12 bolt you can ignore this. However, if you have a ten bolt rear it will have 28 spline axles and an 8.2" dia. ring gear with a small dia. shaft pinion gear. It is stronger than a 7.5" late model ten bolt only marginally. The "Corporate" ten bolt rear end first appeared in 1972 and was designed to replace the twelve bolt rear end. It was a compromise between the larger stronger 8.785" dia ring gear that was used in the 12 bolt, with the same 30 spline axles used in the 12 bolt; compared to the 28 spline 10 bolt rear (some say they are not interchangeable, but if you grind a little off the end of a 12 bolt axle it will slip right into a Corporate 10 bolt rear end and allow the C-clip to be installed). The spline count determines the axles diameter with more splines equating to a larger diameter stronger axle (Ford 9" rears for example use a 31 spline axle, which is replaced in the aftermarket race ready rears with a 33 spline axle, Dana 60's have 35 spline axles).

The problem you will encounter with installing a late model corporate 10 bolt into a 1965-1976 B-body is that it is not a bolt in swap. You will have to carefully remove your old mounting brackets (or buy new ones from Currie or Moser) and then weld them onto the Corporate rear end after you cut off the old brackets and grind down the welds. This is because though both production runs used a four link with coil springs the 1965-1976 cars had parallel control arms and used a panhard bar to center the rear end, while the 1977-1996 cars used two offset upper control arms (set at a 45 angle without a panhard bar) to center the rear end. It is this 45 angle that makes it unadvisable to use polyurethane bushings in the upper control arms in 1977-'96 cars because they will bind when the suspension travels due to the angle and the arc it must traverse causes interference.

The Corporate 10 bolt rear end was used under all 1973-1996 9C1 cars and station wagons, large sedans from Cadillac and Buick and Pontiac. It can be found in pick up trucks as well, but it will be the wrong length unless you are planing to run custom wheels, or to remove the ends of the housing to get rid of the C-clips by means of Ford large bearing kits. There is an odd ball variant of the ten bolt used under Olds cars that have 12 bolts on the inspection cover and press on axle bearings (no C-clips). It is an orphan with out aftermarket parts to change gears ratios or to swap out for stronger aftermarket axles. It was found under '68-'70 Olds only cars and has an 8.3" ring gear.


Big Dave
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post #2 of 9 (permalink) Old 05-14-2007, 07:54 AM
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so my motor set up being i guess mild est. under 400 hp, would a set of 4 series gears be enough? or do i have to look around for a locking carrier? as of now car runs beautiful an pulls great with 2500 stall for being such a big size. im basically tryin to figure out the best way to go for a daily driver.....

"tweed seats wit da digital dash an its squatin jus right in da azz....."

Southern Comfort comin soon......
http://www.cardomain.com/ride/737737
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post #3 of 9 (permalink) Old 05-14-2007, 06:00 PM Thread Starter
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Cool What Gives?

You don't need a heavier duty rear end unless you break the old one. To break a rear end simply bolt on a set of big sticky slicks and take it to a VHT covered track. So long as you are running street tires on bald oil covered asphalt the tire is the weakest link and it will go up in smoke before you will shear an axle or break the teeth off the gears. Consider your car's mass the immovable object. The motor of a high horse big block Chevy is the irresistible force. (I know you have a mild warmed over 355, but work with me) When these two are applied to the rear end something has to give, your choice of tires determines what breaks.


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post #4 of 9 (permalink) Old 05-15-2007, 09:50 AM
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ok i have a set of 70's silverado chrome rally wheels on 235/70-15 whiteletter tires my 4.10 gears should do fine then........right..? lol

"tweed seats wit da digital dash an its squatin jus right in da azz....."

Southern Comfort comin soon......
http://www.cardomain.com/ride/737737
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post #5 of 9 (permalink) Old 05-26-2007, 11:29 PM
 
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should be I have about the same setup in a 64 with 4.10 but 14 x 8 torq thrust along with 225/70 tires, 355 with 1.94/1.60 heads, performer rpm intake, holly 750 all on a 10 bolt and it does fine. Out of the whole I do get alot of traction loss but no wheel hop but I am running a stock stall so take it for what it is worth
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post #6 of 9 (permalink) Old 06-16-2007, 07:39 PM
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Quote:
Originally Posted by md420 View Post
should be I have about the same setup in a 64 with 4.10 but 14 x 8 torq thrust along with 225/70 tires, 355 with 1.94/1.60 heads, performer rpm intake, holly 750 all on a 10 bolt and it does fine. Out of the whole I do get alot of traction loss but no wheel hop but I am running a stock stall so take it for what it is worth
so did u do a carrier also? or jus gear?

im runnin a 2500 stall an dont really wanna go to a posi at the time....but i thought about it while im under the car....

"tweed seats wit da digital dash an its squatin jus right in da azz....."

Southern Comfort comin soon......
http://www.cardomain.com/ride/737737
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post #7 of 9 (permalink) Old 06-17-2007, 02:53 AM
 
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Yea I did the carrier a couple months ago, I'm now having trouble keeping driveline parts in it.
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post #8 of 9 (permalink) Old 10-24-2007, 08:38 AM
 
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Question

Quote:
Originally Posted by Big Dave View Post
If you have a 1965-1976 Impala with a 12 bolt you can ignore this. However, if you have a ten bolt rear it will have 28 spline axles and an 8.2" dia. ring gear with a small dia. shaft pinion gear. It is stronger than a 7.5" late model ten bolt only marginally. The "Corporate" ten bolt rear end first appeared in 1972 and was designed to replace the twelve bolt rear end. It was a compromise between the larger stronger 8.785" dia ring gear that was used in the 12 bolt, with the same 30 spline axles used in the 12 bolt; compared to the 28 spline 10 bolt rear (some say they are not interchangeable, but if you grind a little off the end of a 12 bolt axle it will slip right into a Corporate 10 bolt rear end and allow the C-clip to be installed). The spline count determines the axles diameter with more splines equating to a larger diameter stronger axle (Ford 9" rears for example use a 31 spline axle, which is replaced in the aftermarket race ready rears with a 33 spline axle, Dana 60's have 35 spline axles).

Big Dave
Big Dave, if I had 12 bolt 30 spline axles, could they run with the 30 spline Auburn 8.5 carrier from a 95 SS? Length issues aside.

Thanks!
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post #9 of 9 (permalink) Old 10-24-2007, 04:16 PM Thread Starter
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8.2 inch rear has 28 spline axles. Some; not all 8.5 inch corporate rears have the same 30 spline axles as the 12 bolt rear (you have to grind 5/64th of an inch off the C-clip retainer ring to fit them into the 10 bolt 8.5 inch housing, but yes they will go.

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