i think i am going to purchase a nine bolt posi rear end with disk.but i am not too sure about a couple things.

nine bolt means thats the number of bolts in the diff. cover???

is a nine bolt good or bad???

i have a 91 camaro vert w/ 350 tpi w/ maybe 300hp is 9 bolt big enough??

what do i need to change from my drum to the disk bbrake setup??

any info would be greatly appreiciated...thanks

 

Yes.

A bit stronger than a 10-bolt.

Yes.

Proportioning valve and e-brake cables.

JamesC

 

ok so just to get this right a nine bolt is stonger than a 10 bolt??

and the propotioning valve i can purchase at ...auto zone or advanced>>?

 

Yes but not by very much. Your 91 10 bolt is almost as strong since the 10 bolts started using 28 spline axles in 1990. Your 10 bolt has a 7.625" ring gear. The 9 bolt has a 7.750" ring gear. Both are equally small.

The extra strength of the 9 bolt is from a slightly larger ring gear and a 4 spider carrier. It also has bolt in axles similar to a Ford 9", Dana 44 etc. If it has a posi and the posi is worn out, it's expensive to replace it because it's not designed to be rebuilt. There is little to no aftermarket components for the 9 bolt unless you get them from Australia.

You would be better off just doing a disk brake swap onto your 10 bolt.

 

9-bolt parts from Australia? Why is that? I am in Australia looking for a Camaro (which are pretty rare here), and figured that diff parts would be impossible to find...

 

A bit stronger, yes. The downside is that parts are difficult to come by.

You won't be able to purchase a proportioning valve at an auto parts store. The valve has different thread pitches, depending on year, so that may be a concern with your 91. You might PM Ed Miller (ebmiller88) with your problem as he sells such items. Also, if you change gear ratios, you'll have to consider swapping the drive and/or driven gears to make the speedo read correctly.

JamesC

 

ok that sucks.....how much does that disk brake conversion cost for my 10bolt?? and its expensive just for parts on the 9 bolt posi rebuild.....how expensive???


thanks for that info

 

You should be able to sum costs from the following site:

http://www.flynbye.com/

If you choose to swap to PRB's, this should provide some answers:

https://www.thirdgen.org/forums/faq-...iscs-89-a.html

BTW, the cheapest route would probably be to find an 89-92 (or a fourthgen) disc brake rear.

JamesC

 

well i thought that would be the best thing. the guys says its an 89 t/a rear with 3.27 posi pbr....i dont know what im gonna do now


ohh yea i meant to ask what is pbr???

 

anyone pbr i hear alot about it but?????????

 

PBR is an Australian caliper brand, oem for corvettes, camaros and many other GM cars (aluminum calipers, the cast iron is all delco moraine)

 

thany u everyone 4 your input .....very helpfull