I want everbodies opinion on this subject. I have a 91' Rs with an open 2.73 10-bolt with drum brakes. I want 3.42s and a posi and would like disc brakes. I have been looking around for a 9-bolt rear in the junkyards but was wondering if this is a mistake. Would it be better if I just got 3.42s out of v6 10-bolt and added an aftermarket posi and maybe some aluminum drums? I really don't want to mess with swapping to discs because of the parking brake problems. So which cars should I look for 3.42s in ? If I remember right does somebody sell posi units for $99? What cars should I look for aluminum drums in? Thanks

 

i have both a 10 and 9 bolt rearends. i would like to rebuild one, the question i have is the 9 any stronger then the 10.
the cost will probly just about equal out because i would have to get every thing for the 10 (ring, pinion, bearings, carrier, seals) and with the 9 hopefully i wouldn't need to get a carrier. another question is are the rotors and calipers the same for 10 and the 9, my 10 is from a 84 berlinetta and it had the eaton locker, and the 9 is from a 89 and thats all i know exept ther both disc.
thanks
chad

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85z28
Chad Young
if you want to see my mods go here
now i also have an 87 roc but it has a rod knocking so it wont be rolling for awhilewww.geocities.com/sxt7camaross

 

The 9 bolt is much stronger than the 10 bolt. It has 4 spyder gears vs 2 and is a cone style posi.

Miles

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88 427 Big Block Camaro
(Best 1/4) 12.18 @ 113mph 1.75 60ft
(Best 1/8) 7.76 @ 94mph 1.72 60ft

Currently installing 3.73's into my 9 bolt (YES, it is a 9 bolt & YES they are 3.73's, not 3.70. I currently have 4.10 gear sets and new series 3 posi carriers for sale for 9 bolts )
www.koolmeister.com

 

V6 rear wheel drive cars come with 3.23, 3.42, and 3.73 gears. SLP sells the posi unit for $99, and its only for 90+ 10-bolts with 28 spline axles.

9-bolts are definitely stronger than 10-bolts. They use the same brakes, from 82-88 and 89-92 is the two styles. I put my 91 10-bolt brakes onto my 89 9-bolt when I swapped it.


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1991 Camaro Z28
5.7L 5-Speed (originally 305)
318 RWHP, 419 RWTQ
13.23 @ 107.62 MPH (2.13 60')
Southern California
Member: SoCal F-Bodies
-=ICON Motorsports=-

 

Hmm... Well I have 91' 10-bolt so the $99 dollar posi looks tempting. Were those better gears avalible all years, it doesn't matter which year I get the ring gear from as long as it is the larger 7.65 size? I see six bangers in the junkyard all the time!

 

The 9bolt is definitely stronger, but good luck finding reasonably priced replacement parts for it. I've seen brand new BW posi units going for $800!!

 

Well, I would have to say you are looking in the wrong place! I sell brand new series 3 9 bolt posi units for $445 (~ the same price as a hi perf 10 bolt unit). I also sell gear ratios up to 4.10 along with some other stuff that will be available soon.

Miles

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88 427 Big Block Camaro
(Best 1/4) 12.18 @ 113mph 1.75 60ft
(Best 1/8) 7.76 @ 94mph 1.72 60ft

Currently installing 3.73's into my 9 bolt (YES, it is a 9 bolt & YES they are 3.73's, not 3.70. I currently have 4.10 gear sets and new series 3 posi carriers for sale for 9 bolts )
www.koolmeister.com

 

i know this is a stupid question, but are all 9 bolts posi?

 

thanks everyone for the help with my question
and hopefully i will be ordering gears and install kit from 427 in the next couple of months.


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85z28
Chad Young
if you want to see my mods go here
now i also have an 87 roc but it has a rod knocking so it wont be rolling for awhilewww.geocities.com/sxt7camaross

 

Some people have told me that all 9 bolts were posi and disk brakes, but I have a 9 bolt in the gargage with 3.08 and open carier with drums. I was also told that the 3.08 came in only the 10 bolts but it has 9 bolts and I looked up the number on it in a book I have and it lists it as a 3.08 open diff. The housing has the same (I think casting number) as the one in my car. So obviosly they are all not posi, but most are.

Ben

 

Miles which of the 3.45 3.73 and 4.10 are the strongest ? I'd like to run a 3.45 but if the 3.73's are stronger then i'd go with them, and i'd say if you got a 9 bolt with a 3.08 then you got a bolt missing out of it.

 

OK, I decided to keep my 10-bolt since my 305 is also here to stay so I don't have to worry about punishing it too much. I goin' to nab some gears out of a v6 and get a SLP posi. I want to find some aluminum drums because their lighter and they will look better through my wheels. Two questions though. Is their a specific breakdown of which v6 cars got which gears? An option code maybe? I don't want to have to pop covers and count teeth all day long. And which cars had aluminum drums? Will drums off of another car ( like a G-body or somethin' ) fit? I've only looked at f-bods for these parts maybe I search look in other cars?

 

Oops, another question. I have 2.73s right now. So I have a 2-series carrier right? If I get 3.42s out of a junkyard rear, I need to buy a spacer to adapt them right? Who sells these?

 

If you get the SLP Posi--the posi is part of the carrier and is 3 series. S-series pickups are another good place to get used gears. 7.5 or 7.625 doesn't matter. New gears really aren't that expensive. Don't forget about the bearings and install kit you will need for the SLP unit.

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350 with stealth intake, holley carb, 470 lift cam. 700r4 with .5 boost valve, vette servo, tci lock-up kit, B&M megashifter. Richmond 3.73 gears, powertrax locker, timkin bearings, synthetic lube. Custom 3 inch single into 2 2.5 pipes. 1 1/2 drop springs, 1 5/16 solid front sway bar, 1 inch rear bar, custom subframe connectors, custom LCA relocation brackets. Kobel ground FX, currant red metallic paint. Lots of other stuff...
82camaro

 

Well, not to be picky, but did you remove the cover and actually inspect and/or count the teeth of the ring and pinion to verify what gear it has in it? And does the cover have the rubber plug in it?

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1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club

 

Typically, the numerically lower the ratio, the higher the strength. An exception to that is the 3.73 vs 3.70. The 3.73 actually has 11 teeth on the pinion (vs 10 on the 3.70) making it stronger.

Miles

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88 427 BBC Camaro
7.76 @ 94 (1/8 mile) 10/01
12.18 @ 113 (1/4 mile) 10/99
I have brand new series 3 9 bolt carriers and gear sets to 4.10 available for borg warner 9 bolts. Check my web page for more info.

http://www.koolmeister.com

 

Yes the 9 bolt is much stronger than the 10 bolt, probably about as good as a Dana44, but the only problem it is hard to find gears and parts for it. Much easier/cheaper with the 10 bolt.

 

Ok, the SLP posi is for the 3-series carrier. If I put the junkyard 3.42s in my 2-series carrier and use the spacer to adapt them ( I know they make these, just can't remember where ), can I use the SLP posi?

 

Well, I have had the cover off, but did not count the teeth. It does have a rubber plug in it though(did one and not the other?). I looked up the number on the axle though and it said that it was a 3.08 open diff. I also know that it never pulled posi as long as I had it. It did the one legger pretty well though. lol

 

Not anymore! I carrier gears sets up to 4.10 and new series 3 posi carriers along with other stuff soon. All the info is on my page www.koolmeister.com

Miles

------------------
88 427 BBC Camaro
7.76 @ 94 (1/8 mile) 10/01
12.18 @ 113 (1/4 mile) 10/99
I have brand new series 3 9 bolt carriers and gear sets to 4.10 available for borg warner 9 bolts. Check my web page for more info.

http://www.koolmeister.com

 

Yeah, a regular 7.5 or 7.625 inch 10 bolt axle will have a plain steel differential cover with no plugs at all - one piece. The Borg Warner axles have a rubber/plastic plug for checking the fluid level and adding gear lube when needed, that pushes into a hole that is towards the passenger side of the cover. A 10 bolt has a 3/8 inch square drive plug on the passenger side of the center section for checking the fluid level and filling it. It might help to seal the case if you actually counted the teeth on the gears. I'm not trying to prove you wrong or anything - I just haven't heard of the 3.08:1 gear coming in a B/W axle.... Have you Miles? So you looked up the code on the housing itself? What does the RPO code say on the SPI label (list of RPO codes)?

Laterzzzzzzz

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1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club

 

I have heard it mentioned on the board before, but have no data to back it up. If it does exist, it is very rare and I can't even get parts for it.

Miles

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88 427 BBC Camaro
7.76 @ 94 (1/8 mile) 10/01
12.18 @ 113 (1/4 mile) 10/99
I have brand new series 3 9 bolt carriers and gear sets to 4.10 available for borg warner 9 bolts. Check my web page for more info.

http://www.koolmeister.com