If I were hunting for a posi rear end in a junk yard to rebuild for my '67 Bird, what cars would I be looking for and how do I tell if it's posi. Do I have to pull the cover off?

There are a couple of ways to identify a posi without removing the cover. Only one is a positive ID.

1. Find the axle code and match it to posi; won't work if carrier has been changed to non-posi.

2. Look for aluminum tag on bottom right bolt of cover; may be missing.

3. If you can jack up the rear axle and put the car in neutral or drop the driveshaft, turn the rear wheel on one side and the one on the other side will turn the SAME direction if it's posi.

4. Or you can pull the cover.

Did I miss any?

Thanks. What other models and years should I keep my eyes open for that will bolt into a '67 firebird?

You can convert your existing rear to posi. Eaton has parts, you can use original parts, and I'm sure other companies manufacture posi units also. Do you know what you have now?

There are others on this forum who know far more about posi conversions than I do. Mine has one from the factory.

Be on the lookout for factory 4-speed cars with big motors. Chances are likely the car was ordered by an "enthusiast" and they would have ordered a posi rear (or the factory would have mandated it) to go with that combo.

If you look at the list of BOLT ON DISC BRAKE donor cars, these cars will have a bolt in rear. The interchange is limited, so it's hard to bone because most of the crcaces have been picked clean.

This board is probaly as good of a bone picking area, as anyplace. I recall a bad deal between 2 board members, but I think that they finally got things straghtened out. Even so, from what I'v noticed, the parts/money swap usually nets 99.999& satisfaction, and there are lots of f/g/f members of whom I wouldn't give it a second thought about the worries of "mail order" deals.

Even with shipping, you might be better off dealing with f/g/f members because there is a lot to be said about 100% satisfaction. There are guys here who sell f/g/f parts on eBay, and they post, "Hey folks, I'm giving you first crack at whatever, and I want however much for it. If I don't get a bite, in x-days, it's going on eBay.

Where the hell else are you gonna' get such inside connection?

67-69 Firebird and Camaros, 66, 67 nova will fit.
You have to make sure you find one that has the same spring type as yours, as in mono or multi leaf.
The only sure way to tell if its a possi is to pull the cover. I picked up my 12 bolt real cheep because the guy selling it didnt think it was a possi because both axles didnt turn the same way but it was just a wore out possi all I did was put in a new clutch pack and works good now
If your rear end is in good shape and you just want to have a possi. I would just install a Powertrax No-Slip possi. Very simple.

Wade

I wanted to go down this route but junkyard posi's were not available. I decided I wanted the Eaton Posi for the 8.2 BOP instead. I was going to buy new axles, master axle kit, and gears. It was going to cost about $1200. I decided to go a different route. I found a Corporate 8.5 10 bolt rearend out of a 1973 Pontiac Ventura (Nova clone) $150. I bought new Richmond gears off Ebay for $100 shipped, new Eaton posi off Ebay $300 shipped, new high strength axles $200, master kit $90. So for about $300 dollars less I was able to get a stronger rear-end. I scrounged the junkyard for a posi and gears but they had all been picked through. If you could get all the parts from the junkyard you could potential spend around $400 for everything except axles. You could rebuild the posi for another $80.

The reason I went with the Nova rear over a 2nd gen Camaro is the Nova rear is about 1" narrower than the Firebirds rear but the spring perches are in the exact same place. Here is a good article:

http://www.chevyhiperformance.com/techarticles/48518/

The Camaro rear you would have to cut off the spring perches and put on 1st gen spring perches.

The benefits of this Corporate 8.5 swap are:

Stronger rear
Cheaper replacement parts
Direct bolt-in on 1st gen Firebird (if using Nova rear)
and for you, multi-leaf rear leaf springs.

G.J.
68 350 Coupe

What year Nova's are bolt on replacements for the '69 rear multi-leaf axle?

Is the one inch shorter axle difference noticable?

'68 -'74 Nova (X-bodies, actually). Get the diff before you get custom wheels so you get the right backspacing. I think '72 was the first year for the 8.5, earlier was 8.2.
I haven't confirmed it yet but I've heard that the mid '90's Caprice taxis had the 8.5 diff with a 3.42 posi as standard. The unconfirmed part is whether the center section interchanges with the older 8.5's, 'cause I have confirmed the existence of that diff at the local boneyard. Anyone try that yet?

If I move to a '68-'-74 Nova rearend, will I have to modify the driveshaft any?

I've been told you need to shorten the driveshaft by 1". I haven't been able to confirm this yet.

G.J.

Pretty sure any nova from 1968 to 1976. some had 8.5's, most had 8.2's.

My 8.5 came out of a 74 350 nova.

1 inch narrower didn't make a noticeable difference for me, but I run a narrow 215/70/14.

it's true if you install an 8.5 out of a Nova you will have to shorten your driveline an inch (more like 1 1/2 inches, you'll have to measure it) and replace the back u-joint. I did the swap last year.