4th Gen Parts for 3rd Gen
Member
Joined: Mar 2018
Posts: 229
Likes: 48
From: Virginia, USA
Car: 1992 Firebird
Engine: 3.1L LH0
Transmission: Tremec TKX
Axle/Gears: 3.23 Torsen
Re: 4th Gen Parts for 3rd Gen
There's a decent amount of bits from a 4thgen that you could bolt into a thirdgen, depends on what you want to do with your car/ what year 4thgen it is. If it's a 98-02, you could think about taking the brake booster/ master cyl/ all 4 brake calipers/ rear backing plates. Calipers aren't a direct bolt-on (especially if you have a 9 bolt rear), but fairly common swap on these cars. You may need new brake lines in the engine bay for the master cyl, your '87 might not have the metric lines, but it's more of a direct bolt-in. You will need the 4thgen booster if you want to run the 4thgen master iirc, booster should be a direct bolt-in.
You can also take the entire rear axle assembly if you want, 4thgen 10-bolt will bolt into a thirdgen just fine. It'll be about 2 inches wider per side though, so you may have some wheel poke. If you already have a 10 bolt, you COULD consider taking the diff carrier, but you'll need 28 spline axles, and you'll want to make sure it's the right series of carrier. Kinda pointless to do this unless it has something like a Torsen, but it is possible. Just keep in mind that you most likely have the 26 spline axles, which will not work with any 4thgen diff.
Driveshafts are interchangeable, but no real point in swapping yours for a 4thgen one unless the 4thgen has an aluminum shaft, and you have a steel one. Not super important, but once again, it is something you could possibly use.
If the 4thgen has any aftermarket rear suspension parts, like a panhard or LCAs, or a rear sway bar, those can be bolted onto your thirdgen as well. Front suspension is totally different, can't really make use of anything in front of the firewall aside from the brake master/ booster (ignoring engine swaps)
4thgen wheels can be used if you want, but the offsets (especially on the rear) will most likely be different. There'll be threads regarding 4thgen wheels and fitment in the wheel/ tire forum
Gas tanks can be swapped as well, but it's a bit of an involved swap, and the tank depends on the year. I believe the most desirable tanks are the plastic ones from 98 or 99-02.
Exhaust can be used from the cat back, assuming it still follows the factory route, but no real point in taking the exhaust if it's still completely factory.
Probably overlooking a few things, but off the top of my head, that's a good chunk of what you can make use of in a 4thgen without getting too crazy with custom work. Full interior swaps have been done, but not a direct bolt in; the seats will bolt in perfectly fine, though.
You can also take the entire rear axle assembly if you want, 4thgen 10-bolt will bolt into a thirdgen just fine. It'll be about 2 inches wider per side though, so you may have some wheel poke. If you already have a 10 bolt, you COULD consider taking the diff carrier, but you'll need 28 spline axles, and you'll want to make sure it's the right series of carrier. Kinda pointless to do this unless it has something like a Torsen, but it is possible. Just keep in mind that you most likely have the 26 spline axles, which will not work with any 4thgen diff.
Driveshafts are interchangeable, but no real point in swapping yours for a 4thgen one unless the 4thgen has an aluminum shaft, and you have a steel one. Not super important, but once again, it is something you could possibly use.
If the 4thgen has any aftermarket rear suspension parts, like a panhard or LCAs, or a rear sway bar, those can be bolted onto your thirdgen as well. Front suspension is totally different, can't really make use of anything in front of the firewall aside from the brake master/ booster (ignoring engine swaps)
4thgen wheels can be used if you want, but the offsets (especially on the rear) will most likely be different. There'll be threads regarding 4thgen wheels and fitment in the wheel/ tire forum
Gas tanks can be swapped as well, but it's a bit of an involved swap, and the tank depends on the year. I believe the most desirable tanks are the plastic ones from 98 or 99-02.
Exhaust can be used from the cat back, assuming it still follows the factory route, but no real point in taking the exhaust if it's still completely factory.
Probably overlooking a few things, but off the top of my head, that's a good chunk of what you can make use of in a 4thgen without getting too crazy with custom work. Full interior swaps have been done, but not a direct bolt in; the seats will bolt in perfectly fine, though.
Thread Starter
Junior Member
Joined: May 2026
Posts: 3
Likes: 1
Re: 4th Gen Parts for 3rd Gen
There's a decent amount of bits from a 4thgen that you could bolt into a thirdgen, depends on what you want to do with your car/ what year 4thgen it is. If it's a 98-02, you could think about taking the brake booster/ master cyl/ all 4 brake calipers/ rear backing plates. Calipers aren't a direct bolt-on (especially if you have a 9 bolt rear), but fairly common swap on these cars. You may need new brake lines in the engine bay for the master cyl, your '87 might not have the metric lines, but it's more of a direct bolt-in. You will need the 4thgen booster if you want to run the 4thgen master iirc, booster should be a direct bolt-in.
You can also take the entire rear axle assembly if you want, 4thgen 10-bolt will bolt into a thirdgen just fine. It'll be about 2 inches wider per side though, so you may have some wheel poke. If you already have a 10 bolt, you COULD consider taking the diff carrier, but you'll need 28 spline axles, and you'll want to make sure it's the right series of carrier. Kinda pointless to do this unless it has something like a Torsen, but it is possible. Just keep in mind that you most likely have the 26 spline axles, which will not work with any 4thgen diff.
Driveshafts are interchangeable, but no real point in swapping yours for a 4thgen one unless the 4thgen has an aluminum shaft, and you have a steel one. Not super important, but once again, it is something you could possibly use.
If the 4thgen has any aftermarket rear suspension parts, like a panhard or LCAs, or a rear sway bar, those can be bolted onto your thirdgen as well. Front suspension is totally different, can't really make use of anything in front of the firewall aside from the brake master/ booster (ignoring engine swaps)
4thgen wheels can be used if you want, but the offsets (especially on the rear) will most likely be different. There'll be threads regarding 4thgen wheels and fitment in the wheel/ tire forum
Gas tanks can be swapped as well, but it's a bit of an involved swap, and the tank depends on the year. I believe the most desirable tanks are the plastic ones from 98 or 99-02.
Exhaust can be used from the cat back, assuming it still follows the factory route, but no real point in taking the exhaust if it's still completely factory.
Probably overlooking a few things, but off the top of my head, that's a good chunk of what you can make use of in a 4thgen without getting too crazy with custom work. Full interior swaps have been done, but not a direct bolt in; the seats will bolt in perfectly fine, though.
You can also take the entire rear axle assembly if you want, 4thgen 10-bolt will bolt into a thirdgen just fine. It'll be about 2 inches wider per side though, so you may have some wheel poke. If you already have a 10 bolt, you COULD consider taking the diff carrier, but you'll need 28 spline axles, and you'll want to make sure it's the right series of carrier. Kinda pointless to do this unless it has something like a Torsen, but it is possible. Just keep in mind that you most likely have the 26 spline axles, which will not work with any 4thgen diff.
Driveshafts are interchangeable, but no real point in swapping yours for a 4thgen one unless the 4thgen has an aluminum shaft, and you have a steel one. Not super important, but once again, it is something you could possibly use.
If the 4thgen has any aftermarket rear suspension parts, like a panhard or LCAs, or a rear sway bar, those can be bolted onto your thirdgen as well. Front suspension is totally different, can't really make use of anything in front of the firewall aside from the brake master/ booster (ignoring engine swaps)
4thgen wheels can be used if you want, but the offsets (especially on the rear) will most likely be different. There'll be threads regarding 4thgen wheels and fitment in the wheel/ tire forum
Gas tanks can be swapped as well, but it's a bit of an involved swap, and the tank depends on the year. I believe the most desirable tanks are the plastic ones from 98 or 99-02.
Exhaust can be used from the cat back, assuming it still follows the factory route, but no real point in taking the exhaust if it's still completely factory.
Probably overlooking a few things, but off the top of my head, that's a good chunk of what you can make use of in a 4thgen without getting too crazy with custom work. Full interior swaps have been done, but not a direct bolt in; the seats will bolt in perfectly fine, though.
Also, I'm in the process of upgrading my front brakes with a conversion kit and new parts from RockAuto for a 4th gen. I ordered the conversion kit from bigbrakeupgrade.com. I have not done anything with the master cylinder or booster though. It sounds like that is something I should get from the donor car.
Member
Joined: Mar 2018
Posts: 229
Likes: 48
From: Virginia, USA
Car: 1992 Firebird
Engine: 3.1L LH0
Transmission: Tremec TKX
Axle/Gears: 3.23 Torsen
Re: 4th Gen Parts for 3rd Gen
No worries! Booster/ master from the donor car isn't strictly necessary, but if you can get 'em cheap, might be worth doing since you're already doing the LS1 brake upgrade. Just keep in mind that you might need to change out the MC brake lines if your car doesn't already have the metric fittings, can't recall what year Camaros started getting metric. Also, the booster is a pretty big PITA to pull on a 4thgen if it still has the drip tray in place at the base of the windshield, pretty tucked in there.
As far as the rear end, depends on what's in the '00. The rear brakes would almost certainly be an upgrade whether you have drums or the factory thirdgen discs, but the diff itself might not be so different. If your posi is still working well, and you're happy with the 3.23s, then might not be entirely worthwhile to swap the whole rear axle. You can check RPO codes to see what rear gear the '00 came with, but always check the stamping on the carrier gear itself to see what's actually in there, never know if it's been changed over the years.
If you have a factory rear drum car, there IS a way to get the rear brakes bolted onto your thirdgen axle. There's a good writeup on it here, but unfortunately the pictures are gone. You can put the link into the Wayback Machine over on Archive.org, thankfully some folks backed up the page so you can still find the pictures. I did the conversion using this guide about 3 years ago, and while it was a little scary cutting the tops of the axle flanges off, it wasn't too hard of a swap. Hardest part is getting the brake backing plates lined up, but if you take your time and check all the measurements/ alignment/ clearance, it'll be pretty straightforward. One thing I'll say about the guide though, I wouldn't bother trying to unbolt the drum backing plates unless you plan to save them. I couldn't get the dang bolts undone, so I just took a Sawzall and cut through the drum backing plate and the top of the flange where the single bolt passes through. That part needs to be cut off anyways, so it really speeds up the process. Another thing to think about with your car being an '87 is the proportioning valve... don't think the prop valve from a 4thgen will work on account of the ABS and all; in fact, not even sure if 4thgens HAD a prop valve, ABS might take care of that. BUT, any prop valve from a 91-92 will do, maybe a '90 as well. Late thirdgens got the same prop between drum and disc rear cars, so not too terribly hard to track one down. I'm using my factory drum rear prop valve in my '92 with the full 4 corner 98-02 brake swap, been working perfectly for my car since the swap. I did also do the "spring upgrade" in the prop valve years before I swapped to discs, so I'm unsure as to whether or not that'd be necessary. Third Gen Guy on Youtube (McLovin on this site) has videos on the spring upgrade, as well as the 4thgen master/ booster swap, worth checking out if you wanted to see what all is involved.
As far as the rear end, depends on what's in the '00. The rear brakes would almost certainly be an upgrade whether you have drums or the factory thirdgen discs, but the diff itself might not be so different. If your posi is still working well, and you're happy with the 3.23s, then might not be entirely worthwhile to swap the whole rear axle. You can check RPO codes to see what rear gear the '00 came with, but always check the stamping on the carrier gear itself to see what's actually in there, never know if it's been changed over the years.
If you have a factory rear drum car, there IS a way to get the rear brakes bolted onto your thirdgen axle. There's a good writeup on it here, but unfortunately the pictures are gone. You can put the link into the Wayback Machine over on Archive.org, thankfully some folks backed up the page so you can still find the pictures. I did the conversion using this guide about 3 years ago, and while it was a little scary cutting the tops of the axle flanges off, it wasn't too hard of a swap. Hardest part is getting the brake backing plates lined up, but if you take your time and check all the measurements/ alignment/ clearance, it'll be pretty straightforward. One thing I'll say about the guide though, I wouldn't bother trying to unbolt the drum backing plates unless you plan to save them. I couldn't get the dang bolts undone, so I just took a Sawzall and cut through the drum backing plate and the top of the flange where the single bolt passes through. That part needs to be cut off anyways, so it really speeds up the process. Another thing to think about with your car being an '87 is the proportioning valve... don't think the prop valve from a 4thgen will work on account of the ABS and all; in fact, not even sure if 4thgens HAD a prop valve, ABS might take care of that. BUT, any prop valve from a 91-92 will do, maybe a '90 as well. Late thirdgens got the same prop between drum and disc rear cars, so not too terribly hard to track one down. I'm using my factory drum rear prop valve in my '92 with the full 4 corner 98-02 brake swap, been working perfectly for my car since the swap. I did also do the "spring upgrade" in the prop valve years before I swapped to discs, so I'm unsure as to whether or not that'd be necessary. Third Gen Guy on Youtube (McLovin on this site) has videos on the spring upgrade, as well as the 4thgen master/ booster swap, worth checking out if you wanted to see what all is involved.
Senior Member
Joined: Sep 2002
Posts: 988
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From: Nebraska
Car: '89 Formula
Engine: 355
Transmission: 700R4
Axle/Gears: 9 bolt
Re: 4th Gen Parts for 3rd Gen
Front brakes. Get your factory spindles modified and it's a pretty straightforward swap and big improvement.
Thread Starter
Junior Member
Joined: May 2026
Posts: 3
Likes: 1
Re: 4th Gen Parts for 3rd Gen
No worries! Booster/ master from the donor car isn't strictly necessary, but if you can get 'em cheap, might be worth doing since you're already doing the LS1 brake upgrade. Just keep in mind that you might need to change out the MC brake lines if your car doesn't already have the metric fittings, can't recall what year Camaros started getting metric. Also, the booster is a pretty big PITA to pull on a 4thgen if it still has the drip tray in place at the base of the windshield, pretty tucked in there.
As far as the rear end, depends on what's in the '00. The rear brakes would almost certainly be an upgrade whether you have drums or the factory thirdgen discs, but the diff itself might not be so different. If your posi is still working well, and you're happy with the 3.23s, then might not be entirely worthwhile to swap the whole rear axle. You can check RPO codes to see what rear gear the '00 came with, but always check the stamping on the carrier gear itself to see what's actually in there, never know if it's been changed over the years.
If you have a factory rear drum car, there IS a way to get the rear brakes bolted onto your thirdgen axle. There's a good writeup on it here, but unfortunately the pictures are gone. You can put the link into the Wayback Machine over on Archive.org, thankfully some folks backed up the page so you can still find the pictures. I did the conversion using this guide about 3 years ago, and while it was a little scary cutting the tops of the axle flanges off, it wasn't too hard of a swap. Hardest part is getting the brake backing plates lined up, but if you take your time and check all the measurements/ alignment/ clearance, it'll be pretty straightforward. One thing I'll say about the guide though, I wouldn't bother trying to unbolt the drum backing plates unless you plan to save them. I couldn't get the dang bolts undone, so I just took a Sawzall and cut through the drum backing plate and the top of the flange where the single bolt passes through. That part needs to be cut off anyways, so it really speeds up the process. Another thing to think about with your car being an '87 is the proportioning valve... don't think the prop valve from a 4thgen will work on account of the ABS and all; in fact, not even sure if 4thgens HAD a prop valve, ABS might take care of that. BUT, any prop valve from a 91-92 will do, maybe a '90 as well. Late thirdgens got the same prop between drum and disc rear cars, so not too terribly hard to track one down. I'm using my factory drum rear prop valve in my '92 with the full 4 corner 98-02 brake swap, been working perfectly for my car since the swap. I did also do the "spring upgrade" in the prop valve years before I swapped to discs, so I'm unsure as to whether or not that'd be necessary. Third Gen Guy on Youtube (McLovin on this site) has videos on the spring upgrade, as well as the 4thgen master/ booster swap, worth checking out if you wanted to see what all is involved.
As far as the rear end, depends on what's in the '00. The rear brakes would almost certainly be an upgrade whether you have drums or the factory thirdgen discs, but the diff itself might not be so different. If your posi is still working well, and you're happy with the 3.23s, then might not be entirely worthwhile to swap the whole rear axle. You can check RPO codes to see what rear gear the '00 came with, but always check the stamping on the carrier gear itself to see what's actually in there, never know if it's been changed over the years.
If you have a factory rear drum car, there IS a way to get the rear brakes bolted onto your thirdgen axle. There's a good writeup on it here, but unfortunately the pictures are gone. You can put the link into the Wayback Machine over on Archive.org, thankfully some folks backed up the page so you can still find the pictures. I did the conversion using this guide about 3 years ago, and while it was a little scary cutting the tops of the axle flanges off, it wasn't too hard of a swap. Hardest part is getting the brake backing plates lined up, but if you take your time and check all the measurements/ alignment/ clearance, it'll be pretty straightforward. One thing I'll say about the guide though, I wouldn't bother trying to unbolt the drum backing plates unless you plan to save them. I couldn't get the dang bolts undone, so I just took a Sawzall and cut through the drum backing plate and the top of the flange where the single bolt passes through. That part needs to be cut off anyways, so it really speeds up the process. Another thing to think about with your car being an '87 is the proportioning valve... don't think the prop valve from a 4thgen will work on account of the ABS and all; in fact, not even sure if 4thgens HAD a prop valve, ABS might take care of that. BUT, any prop valve from a 91-92 will do, maybe a '90 as well. Late thirdgens got the same prop between drum and disc rear cars, so not too terribly hard to track one down. I'm using my factory drum rear prop valve in my '92 with the full 4 corner 98-02 brake swap, been working perfectly for my car since the swap. I did also do the "spring upgrade" in the prop valve years before I swapped to discs, so I'm unsure as to whether or not that'd be necessary. Third Gen Guy on Youtube (McLovin on this site) has videos on the spring upgrade, as well as the 4thgen master/ booster swap, worth checking out if you wanted to see what all is involved.
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