I have heard from some referances that around 400 hp you are on the verge of breaking a 10 bolt posi and say you need to up to a 12. I thought a 10 bolt could withstand a little more than this kind of power. True?

It depends on the type of tires and gear ratioo, and how the car is driven.

3.73s and 15x7 stock Road Kings.

Put a 12 bolt in when the 10 bolt breaks for the second time.

Dear 69Camaro dude:

good question. I have been researching this same question for about 3 months. There is no "horsepower" answer to your question, other than somewhere between 400 and 600 I would say. It depends on your gear ratio, automatic or manual trans, if auto - does it have a transbrake, tire size (height and width) traction control, suspension type, engine horsepower, etc.

Also, in your subject name, you mention "10-bolt". you did not say what size ring gear you are talking about. Is it a 8.2", 8.5" or 8.6" or what? for example I know that the 8.5" 10-bolts are very strong and many guys race them. In order to make those 8.5" 10 bolt's hold up to added power and torque you will need to do what I am doing this winter on my 72 Nova (don't hate me because its a Nova. I can't afford a Camaro like you "rich" guys)

1) replace the original ring/pinion with new aftermarket performance setup with the gear ratio of your choice. (about $150)
2) replace the original axles with aftermarket 30-spline (or greater) axles (about $235 for the pair)
3) replace the original carrier (differential) with aftermarket 30-spline (or greater) type (Eaton posi or TruTrac type) (about $400)
4) have a professional welding shop weld the steel axle tubes to the cast iron center section using TIG Nickel rod (a guy in my neighborhood said he would do this complete for $125)
5) replace the stock 10-bolt housing cover with a performance aluminum cover with 1/2" studs that put pressure on the carrier bearings caps when tightened down. This is also called a "girdle" because it supports the bearing caps, etc. (about $140)
6) you will need a installation kit when doing all this stuff (about $100)

how strong is the GM 10-bolt 8.5" setup?

checkout this article from Chevy High Performance Magazine. There are lots of guys running 8's and 9's in the 1/4 mile with this setup.

http://www.chevyhiperformance.com/techarticles/48518_posi_10_bolt_upgrade_install/

have fun

lee

I like Uncle Bill's answer better. LOL

ORIGINAL: z28pete

I like Uncle Bill's answer better. LOL


dear Z28 dude:

I too agree with you about Uncle Bill's response. If it breaks twice - go with a 12 bolt. However, having said that, the 8.5 10-bolt if done right won't break. Getting the 8.5 10bolt setup correctly will cost about $1100. Purchasing a used rebuilt 12 bolt all ready to run will cost about $1600. Purchasing a all new 12 bolt from someone like Moser Engineering will cost about $1800 to $2300.

If you have the money (I don't [:'(]) buy the Moser 12 bolt setup and you're done. If you have to be frugel like me, do what I said to do with the 10 bolt in my earlier response.

Lee