Technical 1956 cadillac rear end question

So guys I am in need of changing the rear end ratio in my 1956 cadillac. The stock is 3.07 and the sweet spot i need is 3.73 for my new drivetrain. I am also wanting to go to a posi. Can someone tell me what rear end is in my car. I was originally thinking 8.2 10 bolt but now i am not so sure.

thanks in advance for the help

 

I don't know exactly what GM called that rear end in those days, but I believe it's a long way from what was built in the decades after.

If you want a 3.73, I'd look at swapping the whole rear axle ***emble for something much newer. A GM pickup would be a good place to find a 3.73 posi and also, for many years, the 5" bolt circle that matches your current wheels.

You can start your search by jacking up the rear of you Caddy, remove the wheels and measure the width of the rear end, from wheel mounting surface (aka WMS) one side to the other. Don't get ****ed into 'backing plate to backing plate' measurement.....it's not very helpful in most cases.

Ray

 

anyone have any more info. I think it is a 55p 8.2 10 bolt rearend. I do not want to change the rearend unless i have no other option.

thanks in advance

 

If you have the factory housing, find an 86 series commercial 3rd member. Should be in the high 3s or so. Take a picture ...

 

If you can find one cadillac made a 3.31 rearend for elderados and powerpack optioned cars in 56

Sent from my LGLS990 using The H.A.M.B. mobile app

 

You might want to search out a Cadillac forum and find out who rebuilds rear ends. for the collectors You can't ship a complete rear end due to the cost but maybe just the pumpkin.

Charlie Stephens