What's a posi rear end? I'm stupid. I'm looking at buying a 78 Firebird and it currently has a posi rear end. It's not listed in the Ebay auction so he's probably going to pull it before its sold. He sais the posi is completely rebuilt. This guy is a mechianic. He wants like $1000 to keep the posi in. Does that sound worth it? Thanks Any info would be appreciated.

The car wouldn't be used for racing, just a fun driving car.

 

Posi is a generic term for a limited slip axle. GM calls theirs Posi-Traction (hence the "Posi"), Ford calls their Traction-Lok, Mopar's is Sure Grip. Uses clutches in the differential assembly to limit the slip difference between the left and right wheels when heavy acceleration is encountered. For $1000, I'd say that guy is smoking guano, unless it's like an Auburn or Torsen differential or a locker, like a Detroit Locker. Hell, new Auburn Pro diffs are like $6-700 depending on where you shop.

 

I think he's valuing it on the fact that the rear end is completely rebuilt. He normally works on Cameros and says he would just throw in some other axle he had lying around if he didnt get a good price on the auction. Looking at it now, he's not going to.

He sounds like a Utah Redneck. He says he has to many cars laying round his house he's got to get rid of this one.

 

Who in their right mind would want to buy a '78 Firebird? Well, besides some redneck stuck on a 'Smokey and the Bandit' kick. Every single Firebird/ Camaro I've ever seen or ridden in was a POS rattletrap with horrendous suspension. And if you're a young male, it's like waving a big red flag at the cops. Assuming you can keep it on the road.

 

Outch. We'll I'm an aspiring redneck and I love smokey and the bandit so deal with it.

 

I also want a 78 to 81, Firebird, I want a Formula with a 400 and four speed, T-roof They had rear disc brakes and are cool in camparison to the mustang, or dodge product of the same years. One problem, Pins and bushing's in the doors could not support the whieght of the door, Every firebird/z28 I see have sagging doors.

 

I'd dig one of those turbo T/A's that came out in 1980.

 

$1000.00 for a G.M. Posi??? Unless that is some kind of WAY special axle he is Nucking Futs. If is just the run of the mill 10 bolt with the weak G.M. posi unit it is worth a fraction of that. Now if it is a 12 bolt with new, Strange (or any other reputable brand) axle shafts and an GOOD Auburn, Eaton etc. then it might be worth it. It really comes down to what all that axle has had done to it. I would find out for sure what it has before I laid that much money down on a G.M. axle. 10 bolts are a dime a dozen, they used them in everything so they are easy to find and parts are cheap.

Joe

 

Well I have an 81 Trans-Am that I've had since my 18th birthday over a decade ago. The RTS Suspension with 3/4 in. sway bars kicks Butt and dosen't even worry about taking names. For back country dirt roads no they are not any fun. But a long winding paved side road and thats a heck of a good time. I live 7 miles from Rt 66 and it rocks to cruise up and down in it or for some spirited driving either one. But if you need to get to the next town faster Intersate 44 is runs along Old 66 and is just as much fun in it too! Cruising town is great! When I was single there was not a night of the week that it was not loaded down with 3 hotties, and rarely the same ones.

As far as the rearend, 1K is to much for it. If it was a locker rear end then he would be advertising it as a locker especially if it was a DetroitLocker. Posi is as described before with the clutches but older ones like that are a dime a dozen. You can pick up an older complete posi rear end with 4:11 gears for less than $400 at the salvage yard all day long.

Limited slip is more like the single track rear ends in some of our trucks. The drive tire (ussally the passenger side rear) spins 20 times and the other dosent then it switches power to the other one.... err sometimes anyway

Lockers are a ratcheting rear end, give a solid hook up of both tires and use ratchets to allow the outside wheel to turn faster when the vehicle is turning corners. Lockers have a very distinctive clicking sound as the car turns. Just for the detroit locker gear assembly alone, to put in a housing is $700. As far as I know todate they have never been an OEM option in anything.