Interesting differences in 91-92 Birds
Thread Starter
Joined: Jun 2005
Posts: 8,122
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From: NC
Car: 91 Trans Am
Interesting differences in 91-92 Birds
Two parts often interchanged are actually different
On top is the air dam off my 91 GTA
On the bottom is the air dam off my 92 firebird
You can see the 91 uses a 2 piece design for no apparent reason
The front section is just bolted on there and really doesnt do ANYTHING
The rear section is the same P/N for both years


The noses and front ground effects for 91 and 92 are actually year specific, but can be modified for either
In the picture the nose is off the 91 GTA and the ground effect is off the 92
Notice the 91 uses only 3 bolts to secure the front, while the 92 uses 4
They also changed the size of the bolts between the years, 8mm for 91 and 10mm for 92

So, for 99.9% of you readers, this info wont be much use. The .1% of you who are doing a 100% original restoration in years to come will, when choosing what to use and what not to
On top is the air dam off my 91 GTA
On the bottom is the air dam off my 92 firebird
You can see the 91 uses a 2 piece design for no apparent reason
The front section is just bolted on there and really doesnt do ANYTHING
The rear section is the same P/N for both years


The noses and front ground effects for 91 and 92 are actually year specific, but can be modified for either
In the picture the nose is off the 91 GTA and the ground effect is off the 92
Notice the 91 uses only 3 bolts to secure the front, while the 92 uses 4
They also changed the size of the bolts between the years, 8mm for 91 and 10mm for 92

So, for 99.9% of you readers, this info wont be much use. The .1% of you who are doing a 100% original restoration in years to come will, when choosing what to use and what not to
Supreme Member
Joined: Jan 2001
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From: Pittsburgh, PA
Car: 06 SRM M6 GTO, 98 Grand Prix GTP
Re: Interesting differences in 91-92 Birds
thats pretty interesting. That means my 91 bumper has been replaced if you're right, cause it has the 4 holes. I never noticed.
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Joined: Jan 2007
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From: Bastrop, TX
Car: 1988 SC Convertible
Engine: LT-1
Transmission: 700R4
Axle/Gears: 3.23 posi w/PBR's
Supreme Member
Joined: Aug 2004
Posts: 4,168
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From: Marietta, GA
Car: '91 Firebird Convertible
Engine: 305 TBI (LO3)
Transmission: 700r4, Vette Servo
Axle/Gears: 3.27 9 Bolt, PBR disks
Supreme Member
Joined: Jan 2001
Posts: 1,374
Likes: 2
From: Pittsburgh, PA
Car: 06 SRM M6 GTO, 98 Grand Prix GTP
Re: Interesting differences in 91-92 Birds
you know, I was just thinking that maybe that top one was damaged, the previous owner got another piece and bolted it in there. Unless you're the original owner, in which case, odd.
Thread Starter
Joined: Jun 2005
Posts: 8,122
Likes: 362
From: NC
Car: 91 Trans Am
Re: Interesting differences in 91-92 Birds
Its not damaged, I really cant think of any reason for it to be on there like that. It doesnt do anything really
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Supreme Member
Joined: Aug 2004
Posts: 4,168
Likes: 3
From: Marietta, GA
Car: '91 Firebird Convertible
Engine: 305 TBI (LO3)
Transmission: 700r4, Vette Servo
Axle/Gears: 3.27 9 Bolt, PBR disks
Re: Interesting differences in 91-92 Birds
Anybody know why there are two vents in the air dam on the driver's side? Is that for a cooling source to.... somewhere?
Re: Interesting differences in 91-92 Birds
I would guess your car is black? Judging from the pics, the first air dam is the same as the second one like you said by part number, but the top one has the cover on it. From what I know, the cover is body colored, the one on my car is red, and is bolted to the actual air dam like yours is. The second air dam in the pic is probably either a replacement for one that got knocked off from hitting a parking barrier. It probably fell off and when the owner got a new one he never got the body colored bolt on piece. Or I believe it could be off a Formula or a Firebird without W68 sport app package bc I don't think they had the body colored piece.
The GFX for the fenders do have different part numberd for 91 cars and now I see why. The bolt pattern difference.
I would also like to know what the vents in the air dam are for. The 85-90 air dams don't have them.
I also need the GFX piece for the drivers front fender!!!! Like everyone else in the world.................
The GFX for the fenders do have different part numberd for 91 cars and now I see why. The bolt pattern difference.
I would also like to know what the vents in the air dam are for. The 85-90 air dams don't have them.
I also need the GFX piece for the drivers front fender!!!! Like everyone else in the world.................
Thread Starter
Joined: Jun 2005
Posts: 8,122
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From: NC
Car: 91 Trans Am
Re: Interesting differences in 91-92 Birds
The cover thing on the air dam is not painted, all my banshee birds are green
Its the same rough texture as the air dam
Both cars have the ground effects package
If I remember right the power steering lines were mounted to the lower rad support in earlier years, but since they were moved infront of the air dam for 91-92, I dont think that was the reason for the vents
The ground effects are not impossible to find
Heres the guy I got my set from
http://cgi.ebay.com/ebaymotors/Fireb...QQcmdZViewItem
Beware they are the 92 style, but if you leave one bolt out they will fit 91 noses
Its the same rough texture as the air dam
Both cars have the ground effects package
If I remember right the power steering lines were mounted to the lower rad support in earlier years, but since they were moved infront of the air dam for 91-92, I dont think that was the reason for the vents
The ground effects are not impossible to find
Heres the guy I got my set from
http://cgi.ebay.com/ebaymotors/Fireb...QQcmdZViewItem
Beware they are the 92 style, but if you leave one bolt out they will fit 91 noses
Last edited by Pocket; Dec 27, 2007 at 08:10 PM.
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Mine does too. 