I have an 1989 Pontiac Formula 350 with an Australian 9-bolt 323 rearend. I would like to upgrade to 373.

Where can I find one inepxensively?
What is needed to make this happen?
Do I need to change housing?

Your help would be greatly appreciated. Thanxs.

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1989 Pontiac Formula L98 Ported Plenum, Edelbrock 6085 Heads, Edelbrock HI-FLO Intake, BBK 52MM TB, Edelbrock TES, FlowMaster 3" Exhaust, Dual Cats, 3.27 Gear, CompuCam 2032 Cam, 1.5 Rollers, Ed Wright FastChip, Accel Super Coil, MSD 8mm Wires, 2500 stall, servo and TransGO.

 

9 bolt parts inexpensive, that's a good one

I have 3.73's for 9 bolts for $295 (other ratios also available). Becareful of others claiming to have 3.73's, they are all the weaker 10 tooth 3.70, not the stronger 11 tooth 3.73. You will also need an install kit, cover gasket and pinion seal and I have that available for $165. No you don't have to change the housing or the carrier if you have a 3.27 carrier. It will support upto (and including) 4.10 gear sets.

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

 

Where can you get those gears for that price at?

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Bright red 87 GTA with I have stock 3.27 gears,2200 stall,B&M shift kit, TRW forged 9.75:1 pistons,comp cams pushrods, edelbrock valvesprings, 462 camel hump heads with 2.02in/1.60ex redrilled for angled plugs, 3 angle valve job, ported and polished, performer RPM intake, mallory fp regulator, edelbrock 750 CFM carb, hei ignition(new) with 40,000 volt coil,No cat, flowmaster 1 chamber mufflers, hedman 1 5/8 full length headers, edelbrock cam with 488/501

Best Run 1/8 mile 8.62 at 84MPH on street tires, Consistantly run 8.8. 60 foot times 2.3

 

88 427 Camaro: Should I go up to 410 gear instead of 373? Do you have 410 gears? Is there a big difference from 327 to 373? This car is not a daily driver, but I would like to drive it on the road as a street car.

Sorry for so many questions, but I am new to this gear stuff. Is it a difficult job for a novice mechanic?

I do not know what else to do to make this car perform better than to replace rear gear.



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1989 Pontiac Formula L98 Ported Plenum, Edelbrock 6085 Heads, Edelbrock HI-FLO Intake, BBK 52MM TB, Edelbrock TES, FlowMaster 3" Exhaust, Dual Cats, 3.27 Gear, CompuCam 2032 Cam, 1.5 Rollers, Ed Wright FastChip, Accel Super Coil, MSD 8mm Wires, 2500 stall, servo and TransGO.

 

I have the following 9 bolt gear ratios available (ie for sale) for the price of $295, 3.45, 3.73 and 4.10. Install kits are $165. Series 3 posi carriers are $445.

If you have an overdrive trans, the 4.10 would be a good choice. If you don't have overdrive, I would stick with a 3.73. Just my .02 since you asked.

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

 

Miles: Do I need a series 3 posi carrier?

Is this gear very difficult to install?

Tony

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1989 Pontiac Formula L98 Ported Plenum, Edelbrock 6085 Heads, Edelbrock HI-FLO Intake, BBK 52MM TB, Edelbrock TES, FlowMaster 3" Exhaust, Dual Cats, 3.27 Gear, CompuCam 2032 Cam, 1.5 Rollers, Ed Wright FastChip, Accel Super Coil, MSD 8mm Wires, 2500 stall, servo and TransGO.

 

Miles: Do I need a series 3 posi carrier?

Is this gear very difficult to install?

Tony

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1989 Pontiac Formula L98 Ported Plenum, Edelbrock 6085 Heads, Edelbrock HI-FLO Intake, BBK 52MM TB, Edelbrock TES, FlowMaster 3" Exhaust, Dual Cats, 3.27 Gear, CompuCam 2032 Cam, 1.5 Rollers, Ed Wright FastChip, Accel Super Coil, MSD 8mm Wires, 2500 stall, servo and TransGO.

 

3.27, 3.45, 3.73 and 4.10 ratios all use the same series carrier (aka series 3). It looks like you currently have a 3.27 gear so you should have a series 3 carrier already. Hence you would only need the gear set and the install kit.

Installing gears is usually best left to a shop (or someone that has done it before) unless you have all the special tools. A shop will be $100-200 for an installation.

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

 

Hey miles! How do I get my hands on a set of these? I wnet to your website thinking that might be where to get them but didn't see anything. Do you just operate by email, or phone? I may need some 3.73's after I get the new engine installed (Hopefully soon, it's been about 2 years in the works! I hate having bills!)

Thanks!

Also, I know it's been addressed here before, but how muah power will they hold up to in stock configuration? I plan on driving it, but not abusing it, and an occasional trip to the strip with the engine listed in my sig.


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Working on:
'84 Z28 LG4 305 with 209,000 original miles!
Dual electric fans (from a formula).
9 bolt posi disc rear with 3.27 gears.
145 MPH IROC Speedo
430 HP 350 (ZZ430) Coming soon! (Building it myself, so I don't get those AWESOME valve covers!)

Starting to look like the Kicker poster child!

ASE Certified Master Tech
+ L1 Advanced Engine Performance
+ X1 Undercar Specialist

And....A sig. that's getting way too long!

[This message has been edited by JP84Z430HP (edited December 05, 2001).]

 

I should have a new web page up with all the details over the holidays. Just haven't had time to finish it lately, so right now email is the best way.

How much stronger???? These are OEM tooled gears made by the original manufacturer (until they sold it off recently), so the strength of these gears is the same as OEM. (I will have some other 9 bolt stuff available after the first of the year too.) I have been running a 9 bolt behind my big block for 3 years now (first with the 3.27, then the 3.73 (NOT 3.70)) and pulling low 1.7x 60 ft times. I think if they are built correctly and maintained properly (ie not worn out) they will hold 1.6x times consistantly (without a trans brake or 5k clutch dumps).

Just send me an email when you are ready.

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

 

Is it true that the 9 bolt posi unit is weak?

 

Ummmmm, it was the high performance option rear. It is a good bit stronger than a 7.5 or 7 5/8 10 bolt but not as strong as a 9 in or 12 bolt. Mine has been holding up to my big block for 3+ years now.

Miles

------------------
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'm refering to just the posi unit. I've read many times that the posi units in the 9 bolts "burn out". Do the 9 bolts have a "clutch" style posi or a "cone" style? I have a 3.27 9 bolt in my GTA and I honestly know nothing about it.

 

Miles - what all is included in your install kit?

 

The 9 bolt posi unit is actually much stronger than a 10 bolt as the 9 bolt has 4 spyder gears vs 2 in a 10 bolt. The 9 bolt is a cone style posi.

The install kit includes everything needed for a gear swap and/or a carrier swap (Timken pinion & carrier bearings and races, shims, crush sleeve, ring gear bolts, gear marking compound, silicone, pinion seal, rear cover gasket, install instructions)

Miles

------------------
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

 

That's what I was looking for. Thanks

 

Sorry

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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

[This message has been edited by 88 427 Camaro (edited December 09, 2001).]

 

Are there options for a 2.77 rear?

 

Only to upgrade it to a series 3 posi unit. Sorry.

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