Cadillac rear axle

[crazyliver]

I pulled the 472 from my 1974 Cadillac Calais today. I noticed the heavy *ss driveshaft, and the rear end looks fairly beefy. It is not a POSI, but I wonder if the rear end would hold up in the 84 grand prix better than a stock one, or the 7.5 posi rear end I have out of the 2+2.

The setup seems similar to the grandprix (brackets/mounts, etc). Has anyone thought of using the Cadillac axle during a restoration? Does anyone know anything about the axle?

 

[dogsht]

It would hold up! Fabing it to fit might not b the most cost effective though! I think both posi & a low 3.21 gearset r out their but rare. The gear was put in limos. 28 spline axel, posi, & support cover & welded scepticism tubes is another depending on availibility of an 8.5 & or your et goals for the car. For a more race oriented car Fabing a 12 bolt or Ford 9 becomes more attractive

 

[DRIVEN]

Probably a 12 bolt. I believe that's considered a C-body platform but similar to B-body. Probably not a direct bolt in and too wide but definitely stronger than the stock 7.5 in your GP.

 

[buickestate]

Did that 74 caddy have a rear sway bar?

 

[JBreu]

I agree with Dogshit, who btw is a great contributor, the Caddy rear end will hold up, however the work involved to make it work/fit in our cars is really not worth the trouble...Try to grab a 8.5 rear, 68-72 12 bolt or.....I hate to say it a Ford 9" for your car.....I'm a "keep your GM car all GM", so I have a '69 Chevelle 12 bolt tucked underneath my pride and joy

 

[crazyliver]

Did that 74 caddy have a rear sway bar?

I would have to recheck, but I did not remember seeing one. The car is going for scrap, so if you need anything let me know. I am 2hrs north of London.

 

[crazyliver]

It would hold up! Fabing it to fit might not b the most cost effective though! I think both posi & a low 3.21 gearset r out their but rare. The gear was put in limos. 28 spline axel, posi, & support cover & welded scepticism tubes is another depending on availibility of an 8.5 & or your et goals for the car. For a more race oriented car Fabing a 12 bolt or Ford 9 becomes more attractive

I will never drag it, just looking for something a little fun. I was going to measure it to see how far off it was from a G Body axle, but from the sounds of it it is pretty different.

 

[dogsht]

If its never going to see a drag strip or slicks as mentioned just upgrade your 7.5. A support cover may suffice. http://www.taperformance.com/proddetail ... od=TA_1809

If you want even stronger and or if you want to change the gear anyway and or get a posi you can get 28 spline axles to go with a 28 spline 7.5 posi. Moser or one of them companies make the 28 spline axles for the gbody and fairly reasonably at that. These are much stonger axles. Some S-10s actually came with a 28 spline posi for the 7.5/7.625 additionally some S-10s came with a 3.42/3.73 or 4.11 gear set if you want to save some coin and track down a used posi & gear. But the axles out of an S-10 won't work. I don't remember the online search engine address for it but one of your local salvage yards should have it and be able to locate it used for you. IMO this is the most cost/work effective route for your goals. New (high quality) Eaton limited slip differentials are expensive but new clutches for a inexpensive salvage yard limited slip ie "posi" are only about $90 and you don't need a pro to just change the clutches.

You can additionally weld a bead around the axle where it meets the housing. At this point you would have a pretty darn strong rear and still not have as much money and work as doing a GM 12 bolt or ford 9. Not as strong either but strong enough for anything with regular street tires and on the street. In an ideal world we would all be able to find a cheap fresh 8.5 but thats not likely.

Thanks for the props JBreau

 

[maliburacinfreak]

You can additionally weld a bead around the axle where it meets the housing.

im hoping you mean weld a bead around the axle TUBES where they meet the center housing. :wink:

 

[crazyliver]

I have 2 1986 2+2's that I am wrecking, so I am planning on stealing the 3.08 posi units out of those...