You should get the axle code from the rear axle tube. Stamped on the axle tube to the left or right of the "pumpkin" will be a code. It will read something like "DA 0212 B" which will break down as follows: DA Open 3.08:1 ratio, 0212 Feb 12, B Buffalo. I dont have a complete list of all 1967 codes but it will be a start. Perhaps someone can supply that info after you find it and post it here.

Technically the RPO code for Positraction is G80, but it wont appear on your trim tag. If you have GM documentation (VVS) it will list the options your car left the factory with.

If you are planning on dropping a 700-horse SBC into your Parisienne you should plan on a stronger rear if it isnt a 12-bolt. That kind of power out of a small block is pretty radical and would have to spinning pretty tight to make that kind of power. I suspect that your gearing will need to change to a much higher number. A small displacement engine making power like that will not be a relaxed engine, it will be high-strung and need to keep the revs up. The greater the displacement, the greater the torque, IRRESPECTIVE of horsepower. Moving a big car will take torque, or if not torque then lots of revs and gearing.

I recently installed a posi in my 65 parisienne 12 bolt to handle extra power for my big block. I bought the posi unit and took it and the complete diff housing drum to drum to a reco shop who did the complete job. If you search the threads here you will find a member has recently done just that himself with pictures. If you plan on power increases and have the dough to do this, it is the best way to get that power to the ground along with other drivetrain improvements. 

I have never worked on a rear end assembly but from what I understand it is a matter of setting preload on the crush sleeve and setting the backlash so the ring & pinion mesh properly. Yes, you can upgrade your rear to limited slip. There are several manufacturers that make limited slip differentials to drop in. Theres Powertrax, Auburn and Eaton to name a few. I recommend the Eaton because they are rebuildable while the Auburn is not. Eaton uses clutches to lock; some others use a ratchet mechanism. Eaton was GM's OEM supplier for posi.

Changing your ratio is doable, but if you are running a 3-series ratio then you can work within ratios from 3.08 through 3.70. It is also possible to run 4-series gears but it is not recommended unless you already have a 4-series carrier. If you utilize a 3-series carrier for gearing in the 4-series range you end up using a ring gear spacer to keep the ring gear in contact with the smaller pinion gear. That is not good as the thickness of the ring gear and added spacer put too much strain on the carrier bolts. I would fully expect your 67 to have a 3.08 rear unless your car is running a TH400 from the factory (2.73 gearing). What engine & trans did your car come with originally? Typically they came with 283 Powerglides.

If you want some real feedback on upgrading your cars rear, I recommend searching at Team Chevelle. There are several people there that rebuild rear ends every day and they can give great recommendations. Theres a guy over there named Big Gearhead that can give you all the straight scoop you could ever want.

SGS Welding wrote:

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427carl I think you should consider a posi If you do the beanfest tour it's cooler to burnout both tires. Spectators on both sides of the street deserve to see tires turning to smoke! Lol Besides if your the Carl I think you are tires should still be easy to get! Thanks again Canadian gm fan Your good info has me on the right track.

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         That ok...    I always skip the tour ...  too many fellows driving, after have many many beers....

        Someone will install some gears for me    I'll install a posi, if someone gives me one for free   

57 Pathfinder wrote:

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Look into the True-Trac. It's an all gear limited slip, no clutches to wear out. It's also very smooth and 'invisible' during normal driving, but it works very well when the tires break loose. My other vehicular addiction in K5 Blazers, and I've run several different traction aids in those. Spool, Detroit, and Eaton's explosion prone Gov-Lock. A spool is ugly for anything other than ensuring full power to both wheels all the time...the Detroit was much more civilized, just a little 'locker steer' when shifting and it could be a bit noisy. The Gov-Lock...click, click, boom! lol

Anyways, I've heard nothing but good on the True-Trac for street vehicles.

The crush sleeve is a pain in the arse, but they do make a crush sleeve eliminator for the 12 bolt. Something to look into if you're re-gearing yourself.

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         Thank you....     I do not want a posi.. posi-track- limited slip, or True trac      don't want to spend the money on it...  

         Its totally useless...  for a car that never see the track... OPP around here will tow it away, and you walk home, if you do 130 km in a 80.....     

         Car never races... I just want a little more passing power   I'll get someone, somewhere to JUST add some gears... or I will leave it alone    Last year I drove the car almost 50 miles....

As with all car mods, they are an individual choice and preference Depending on many factors. all our cars are fun to drive and enjoy because they are ours and we built them how we wanted to! I love and appreciate em all! Except goggomobiles, they are hard to love.....

Nice burnout...   I love them  and used to do them    

I have had over 100 muscle cars in 48 years and  love the power and smoke too  

BUT  

I live in a world of enforcement, which makes it too risky to run a car like I used too....    

Drag racing is too competitive (for me) and too long a event...(sitting in 80-90 degree) heat in a old car for hours waiting for  2-3 runs is not fun for me

I just want a little more power up through the gears...     big block and heavy car need torque....   but I am on a budget, and a posi would be  such a waste for me...

The money for a posi will buy me fuel for 2 summers  maybe 3    

If you're planning on putting big power to your big 67. Then first focus ALL your early budget on handling and braking. 

Adding big power to our wallowing barge is a recipe for disaster imop. Make it totally safe first, then build a rear, trans and driveshaft that can handle some torque, then plug in the power and play! I'm currently building a 496 that should produce around 580/600, so I still need some serious work to be done. My saving grace is I'll likely never get grip, so things should tend to survive a little better that way.

Oh, and rear ends can absolutely be built in a backyard shed with just a few simple tools and skills. If I can do it, anyone can.  I successfully converted my open 12 bolt, to a Eaton posi with a 3.55:1. And so far so good. 

But there is step by step help available from the good members here if you ever need it.

Cheers,