What rear axle came in an 87 GTA 5.7?
Joined: Aug 1999
Posts: 19,282
Likes: 103
From: Lawrence, KS
Car: Met. Silver 85 IROC/Sold
Engine: 350 HO Deluxe (350ci/330hp)
Transmission: T-5 (Non-WC)
Axle/Gears: Limited Slip 3.23's
Thread Starter
Member
iTrader: (2)
Joined: Oct 2005
Posts: 198
Likes: 0
From: Crestview, Fl
Car: 87 GTA
Engine: tpi 350
Transmission: 700r4
Re: What rear axle came in an 87 GTA 5.7?
Thread Starter
Member
iTrader: (2)
Joined: Oct 2005
Posts: 198
Likes: 0
From: Crestview, Fl
Car: 87 GTA
Engine: tpi 350
Transmission: 700r4
Re: What rear axle came in an 87 GTA 5.7?
Well, my car has a LS 10 bolt... Anybody know how I can identify where it came from?
Is the 10 bolt better or worse than a 9 bolt?
Is the 10 bolt better or worse than a 9 bolt?
Moderator
Joined: Jul 1999
Posts: 17,271
Likes: 171
From: 51°N 114°W, 3500'
Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: What rear axle came in an 87 GTA 5.7?
Depends how you look at it. Technically the 9 bolt is a little bit stronger but not by much. A 10 bolt can be better because it has greater aftermarket support.
Neither is great compared to using a third gen Dana 44, if you can find one, or using an aftermarket 12 bolt, 9" or Dana 60.
What's an LS 10 bolt?
The diffs under third and fourth gen cars are virtually identical with some slight variations. In 1990, they were upgraded to 28 spline axles from 26. The ring gear size increased slightly from 7.5" to 7.625 around 1986. Depending on the engine, transmission etc, they could come with or without a posi and in just about any gear ratio. Brake options changed over the years but that adds nothing to the strength of the diff itself. A fourth gen diff is about 2" wider on each side. A diff in a V6 car is really identical to a V8 car's diff with no difference in strength.
Neither is great compared to using a third gen Dana 44, if you can find one, or using an aftermarket 12 bolt, 9" or Dana 60.
What's an LS 10 bolt?
The diffs under third and fourth gen cars are virtually identical with some slight variations. In 1990, they were upgraded to 28 spline axles from 26. The ring gear size increased slightly from 7.5" to 7.625 around 1986. Depending on the engine, transmission etc, they could come with or without a posi and in just about any gear ratio. Brake options changed over the years but that adds nothing to the strength of the diff itself. A fourth gen diff is about 2" wider on each side. A diff in a V6 car is really identical to a V8 car's diff with no difference in strength.
Thread Starter
Member
iTrader: (2)
Joined: Oct 2005
Posts: 198
Likes: 0
From: Crestview, Fl
Car: 87 GTA
Engine: tpi 350
Transmission: 700r4
Re: What rear axle came in an 87 GTA 5.7?
Depends how you look at it. Technically the 9 bolt is a little bit stronger but not by much. A 10 bolt can be better because it has greater aftermarket support.
Neither is great compared to using a third gen Dana 44, if you can find one, or using an aftermarket 12 bolt, 9" or Dana 60.
What's an LS 10 bolt?
Neither is great compared to using a third gen Dana 44, if you can find one, or using an aftermarket 12 bolt, 9" or Dana 60.
What's an LS 10 bolt?
LS = Limited Slip
Trending Topics
Joined: Jul 1999
Posts: 10,950
Likes: 26
From: Orange, SoCal
Car: 1990 Pontiac Trans Am
Engine: 355 TPI siamesed runners
Transmission: Tremec T56
Axle/Gears: 12-Bolt 3.73
Re: What rear axle came in an 87 GTA 5.7?
Yeah it was probably swapped in. An 87 GTA with a 5.7L TPI should have a 9-bolt 3.27 ratio as Stephen first said.
Thread
Thread Starter
Forum
Replies
Last Post
LT1Formula
Engine/Drivetrain/Suspension Parts for Sale
7
Aug 20, 2015 09:36 PM
Dialed_In
Firebirds for Sale
2
Aug 20, 2015 01:45 PM
