10 bolt rear end strengthening

daveshapellSVT · 09-18-2007, 07:59 PM

hi i have a 91 formula and i'm upgrading the heads and cam. i have a gm 10bolt rear end with stock 3:23 gears and i'm wondering what i can do to beef up my rear end? i wanna make sure it can handle hard launches and tire heating cycles with drag radials. I know some cars have rear axles that can be swapped out for beefier ones. do they make after market axles for the 10 bolts? what do you guys think i should do?

Morley · 09-19-2007, 02:51 AM

It all depends on how much power you are planning on putting through the rearend. If you have over 400ft/lbs of torque I would drop the drag radials in favor of some good street tires. You want some slip or you will start destroying parts, like differentials, transmissins, driveshafts, etc.
That said, I would look into getting an Auburn limited slip carrier (if you don't want the expense and fabrication headaches of using a Ford 9 inch) And an aftermarket ring and pinion gear.
The Auburn carriers were the factory replacements for the weak Saginaw limited slip carriers found in third gens. These units are plenty strong and durable, I'm putting over 400 ft/lbs through mine (on street tires) with 3.42 gears.
The "all out" would be to get either the Ford 9 inch setup for third gens...I think its over $1500 from Moser.
Next would be to get the Auburn carrier & gears, Strange or Moser axles and C-clip eliminators (especially if you don't have rear disk brakes and plan on doing a lot of track time)
After that you will HAVE to get subframe connectors or you'll wreak havoc on the unibody. Then you'll have to make sure the transmission is going to be up to the task of transferring lots of power.

89IROC&RS · 11-07-2007, 01:08 PM

something else to possibly look into is trying to find a 9 bolt rear end. not a ford 9 inch, a gm/auzzy 9 bolt rear. they are very strong, not alot of people know about them, so info is hard to find, but they have been said to be as strong as a Dana 44 axle. they came in 2.77, 3.27, and 3.77 ratio's from the factory i believe. as opposed to the 2.73, 3.23, and 3.73 ratios in the smaller 10 bolt axles. the strength comes from a 7.75in ring gear, and a much shorter distance between the diff caps. reducing flex and the chance for breakage. i dont know if this site still works... www.9bolt.com, that guy was the last one i knew of who sold replacement parts and rebuild kits, i hope he's still doing it, because i need to get some stuff for my rear end. nice thing is they also came with disk brakes on some of the cars. using the 1LE aluminum calipers, at least in 89.

The last one i bought, a few years ago, was around 300-400 bucks. and was the disk brake setup. If you cant find one, are interested, and dont mind a project. i will have one available, hopefully in a few months. It will be a series two carrier with 2.77 gears though. in order to run deeper gears, youll need to buy a series three carrier and gearset. which im pretty sure only that guy can get for you.

its a bit of a pain to do, but the cool factor his very high, especially seeing as they were factory equipment.

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