What hp to switch from 10 to 12 posi rear?
 

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?

RE: 10 Bolt vs 12 Bolt posi rear
 

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

RE: 10 Bolt vs 12 Bolt posi rear
 

3.73s and 15x7 stock Road Kings.

RE: 10 Bolt vs 12 Bolt posi rear
 

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

RE: What hp to switch from 10 to 12 posi rear?
 

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/te...grade_install/

have fun

lee

RE: What hp to switch from 10 to 12 posi rear?
 

I like Uncle Bill's answer better. LOL

RE: What hp to switch from 10 to 12 posi rear?
 

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