Which is better? I have a stock 91 disc brake 3.42 10-bolt I upgraded with a SLP HD Torsen. I could get a stock 89 3.45 rear end if I wanted one. Do I? I hear the 9-bolts are stronger than 10-bolts but is it stronger than my 10-bolt with the upgraded posi? This is my daily driver and weekend drag racing car.
I searched the tech archives and it looks like most of the questions are asking 9-bolt to 10-bolt, so maybe I dont want to swap...

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1991 Camaro Z28
5.7L 5-Speed
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
Webmaster: ICON Motorsports

 

I just swaped in an IROC rear end. It's stronger than the 10 bolt. The only problem is that it's harder to find parts for the BW rear. If you want gears lower than somewhere around 3.57 then you cant get it with the BW. I think that that's the lowest gear for the BW. But teh BW is still stronger. I would go with the BW which I'm going with.

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Chris
91 RS 305 TBI
Team Neo Blood

 

Kevin the 9 bolt is ALOT stronger than the ten bolt and you wont have c -clips anymore either.

 

My 9 bolt is surviving with 1.6xx 60 foots and high 11, low 12 1/4 mile passes however I'm building a drag race 10 bolt just so I can get a lower gear ratio.



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Stephen's racing page

87 IROC-Z Pro ET Bracket Race Car and knocking on the SuperPro ET class
383 stroker (carbed) with double hump cast iron heads and pump gas
Best ET on a time slip: 11.857
Best corrected ET: 11.233
Best MPH on a time slip: 117.87
Best corrected MPH: 125.46
Best 60 foot: 1.662

Racing @ 3500 feet plus density altitude!

Member of the Calgary Drag Racing Association

 

The times in my signature are from the stock 9-bolt rear with SLP 3.70 gears from 1991. No problems...

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1989 Formula 350, 10.5:1 383", TFS heads, Comp Cams blower grind, TPIS Mini-Ram, BBK 58mm throttle body, Vortech S-trim 15 psi, DFI, 42# injectors, S/X fuel system, MSD ignition, SLP 1.75" headers, Flowmaster exhaust, MW Racehouse 700R4, Currie 9" w/3.50 gears, Jeg's sfc's, Jeg's lca's, S&W 8-point rollbar, lookin' stock street racer...

Best ET: 10.796 @ 125.8 on 16" Sportsmans...

 

Kevin,

You remember my install a few months ago? The 9-bolt is WAY stronger then the 10-bolt. It has to do with the geometry and such of the casing and not as much with the actual ring gear thickness and all. That is why you can spend $175 for the differential cover to strengthen up a 10-bolt.

Parts are about twice as much for 9-bolts then 10-bolts... except brake parts. My pads are the same as the ones for the front disks. They changed the brake caliper style in 87 I think (could be 89). The later model is better.

I have 3.27s that came with the rear. It is the perfect gear for a 700r4. You can get 3.42s and 3.70s I think still.

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock... all the suspension stuff... 9-bolt posi disk is in... K&N filter... 93 octane...

I got the GO... I need the SHOW... Interior is next!

 

So you guys all agree I should swap my 10-bolt for a 9-bolt, for drag racing?

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1991 Camaro Z28
5.7L 5-Speed
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
Webmaster: ICON Motorsports

 

Hey, your not thinking of coming to my house and taking my 9-bolt while I sleep, eh? You know my vote.

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George P. Lara
1984 Z28 High Output
Proud Member of SCFB
V6 T5 For Sale

 

Swap in the 9 bolt. It only costs like 30 bucks. Well that's all I had to pay for parts.

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Chris
91 RS 305 TBI
Team Neo Blood

 

what are you gonna do with your old rear

 

Its going to be swapped to the guy with the 9-bolt.

 

oh well, shipping would have been a bitch anyway