So, I just picked up my first 3rd Gen that's got a straight body almost ready for paint, t tops with no rust and a bunch of suspension upgrades and bolt ons for cheap. Still has the 5.0 that idle like it has a crazy cam in it. Not because it does, something's wrong, but that's for another time unless you already know lol. I'm here because previous owner slapped in a 4th gen rear with discs and seemed to like how it looked, I however am not a big fan. My question to yous guys is what are my cheapest options to get back to 3rd Gen width so I can keep the gta wheels? Is there an aftermarket 4th gen gta that would have correct backspace (can't find any without buying an entire set and even then idk how the front would look with them)? Kinda thinking finding an old 3rd Gen rear and stealing the discs off the current 4th gen might be the cheapest route to go unless you gurus have any better ideas. I'm not completely opposed to something like a set of boss style rims or ridler 695s if I can get them to fit correctly but I kinda like the GTAs, just want em tucked back in properly

 

That does look kinda like cold leftover yesterday's BUTT doesn't it?

Since there were no "4th gen GTAs" made, there are no such wheels, from GM. There might be aftermarket imitations though, iunno about that. IMO locating such a wheel would be your best option, if it exists. People on the Wheel & Tire forum on this site might know more about that than most of the rest of us.

I think there are also people that can cut the centers out of the wheels and weld on new rims with any arbitrary backspacing. Not sure how much of a tab that would run up though. Again, people on that other forum might be more familiar with such things.

While it would certainly be "possible" to put the 4th gen brakes on a 3rd gen rear, to avoid downgrading to the even weeeeenier early-model (88-back) axles, you'd need to come up with a 89-up disc rear to do that to. There aren't awholehelluvalotta those just laying around waiting to be given away or anything. It's probably possible to convert a drum rear to discs butt it's not a bolt-up. Some fabrication (not all that much, butt hay, it's BRAKES) will be required.

 

Sir, I take great offense at the amount of fun you had with the double XL posterior of my poor plucked chicken! I'd have to challenge you to a duel if I wasn't so sad you had equally as much bad news 😭

I'm not opposed to a little fabrication. There's a really good video on YouTube about stealing 4th gen brakes for older drum cars but like you said, I'd still have the scrawny old rear. I do plan on LS/4l60 swapping the car, but I'm not gonna go crazy with it. Mild cam and be done. That said, how weak are the older rears in these cars? Would it die a quick painful death with mild LS guts?

 

Depends on how you drive. Power alone doesn't kill these rear ends but traction does. Hard launches combined with sticky rubber = no bueno. If you avoid that, it will live.

 

Kinda depends on how you go about it.

If you take a 3rd gen housing and get the 4th gen brakes onto it, put the 4th gen carrier in it with appropriate new gears of your choice, all new bearings of course, and new aftermarket axles, you'll have done about all you can realistically do to a 7½" 10-bolt. It would be about equal to a 4th gen one at that point, maybe a bit better, since stock axles are such CRAP to begin with.

If all you do is figure out a way to hack the 4th gen brakes onto an early 26-spline-axle one, and leave all the old 26-spline crap in there, the axles will probably be one of the weeeeek points that will protect everything else.

 

Well after some digging around, turns out I live about 2 hours from Hawks. They have used posi/disc 82-88 rears (I'm assuming they'll have 26 spline guts?) as well as 90+ posi/disc rears (likely 28 spline?) for fair enough price considering I won't have to pay for shipping ($550
According to the site)

Obviously I would rather the 28 spline but I didn't think the older rears had discs so I guess it's possible they also had 28 spline considering the posi with disc? They aren't open yet to call but will 90+ be a bolt in application aside from the brake lines and still fit stock 87 model suspension parts and wheel backspacing? Would there be any benefits going 90 model if the 88 and older models are 28 spline?

And thanks for y'all's input btw. My first 3rd Gen experience. Was actually looking for an early 70s Nova when I found this sad big booty chicken in need of some love

 

Right: 88-back are 26-spline, 90-up are 28; 89 could be either but seems they are mostly 28.

No 88 or older will have 28-spline axles & carrier unless someone has put them there. Which while by no means impossible, isn't bloody likely. No "features from the future" from the factory in any case.

Disc brakes were available in these cars since they were introduced in 82. They were the same (cast-iron Delco-Moraine) at that time as what had come in 2nd gen F bodies starting in around 79 or 80. 82-88 will have either drums or those crap cast-iron disc brakes; 89-up will have drums or the MUCH better aluminum PBRs. Discs were quite unusual until 85 when the 9-bolt rear was introduced, and became much more common after that.

The master cyl and combo valve are considerably different between the D-M and PBR systems. Drum ones will work the PBRs quite well but the 2 disc systems don't mix-&-match well together.

Yes all these cars' rears will bolt into any year. There are only acoupla differences. One is that 82-83 used SAE flares on the lines where 85-up used metric bubble flares. 84 was a changeover year so like the 89 axle deal it could be either; early production is more likely to have the old stuff than later builds. And, the parking brake cable system; which I think are mostly the same on the axle, but the part on the body differs. At least, when I put a 91 or so rear in my 83, the parking brake cables on the rear hooked right up to my car. Other people with other combinations seem to run into problems sometimes but I can't recall the details.

 

That's good news, thanks for all the knowledge my guy! Had a crazy day so never got to call Hawks. Hopefully they'll have some 90+s in stock. I was about to buy some fender flares and massage em in and just own the ol girls big butt lol. Crazy part is, the guy did the work to hook up the e brake and slap in all the bmr bolt on suspension stuff and eibach springs but was content with the wheels dangling out there on the 4th gen so now I'll have to undo everything 😭. I got a bunch of boxes to go through this weekend as the car is completely stripped and packed up... He seemed to save everything except the diff itself so that'll help if he left the back half of the cable.

The rear is in good shape, cleaned up and everything so maybe I can make some of the $ back from having to undo this atrocity. So far, $1400 in after buying the new 8 piece t top weatherstripping so I can't complain too much considering all the stuff underneath AND I drove it home.

 

If it were me I would look at 4th gen f-body or corvette wheels and run 1.5 to 2 inch adapters in the front.

 

Sounds like you're tryna but my 4th gen rear! it'll be for sale before too long (hopefully) and you can run it lol. 2"spacer on the front on the roads around here doesn't sound like something I'm interested in.

I actually fixed it running like crap with some super glue. Nipple was broke off the vac can. Hooked that back up and was ripping those old toyos off the back lol. After driving it a bit I think I'm actually gonna get some paint on her before the diff swap back and just cruise the big booty and save up for a better rear. Can't believe how strong it runs with fixing a little 1/4" hose. Didn't expect it to spin both tires without power braking it but she laid it down

 

Spacers and adapters are different things,