8.5 rear swap into my 84??

Hey everyone,
New member here. Just picked up a 84 Caprice 2 dr.
Car has a wicked 406 sbc/TH350 combo; as you can see the rear diff is the weak link in the driveline.
It has the stock 7.5' open rear in it now;
I want to install a built 8.5" (beefy posi unit, bigger axles, gears, etc)
Now, i have heard that the disc brake, posi rears out of the 94-96 Impala SS will bolt right in.
However, I have found these rears to not be as plentiful as i first thought
(they are scarce honestly, supposedly all the circle track guys ate them up already)
Id love to bolt a 3:73 disc brake posi (from a Brougham, apparently) into this car and be done with it  after a little rebuild and new brake prop valve. But i just can't find a complete unit available near me. Ive got a pretty good network of parts sources and I've exhausted all if them (8 junkyards, eBay, craigslist, racejunk,and a lot of 'chevy-friends')
Now my question is; does anyone know where i can find just a REAR DIFF HOUSING for a mid 90's Impala SS;
then i can build it how i like?
Casting/Part #'s?
Parts sources?

Any info anyone can give me would me greatly appreciated. THANKS guys!!!

Check out "Bill" Elvis article in "share with us" forum.

Axle Ratio RPO Code Ring/Pinion Teeth Application
2.56 GM8 41/16 Std. Roadmaster LT1
2.73 GU2 41/15 Std. Caprice L99 (exc. 9C1)
2.93 GW9/GU3 41/14 Std. Caprice LT1 (exc. 9C1), Opt. Roadmaster LT1
3.08 GU4 40/13 Std. Caprice 9C1/LT1 (Police), Std. Impala SS
3.23 GU5 42/13 Opt. Caprice L99, Std. Caprice 9C1/L99 (Police)
3.42 GU6 41/12 Std. 91-93 Caprice 9C1/L05, Std. 94+ Fleetwood w/V4P
3.73 GT4 41/11 Std. 91-92 Fleetwood Brougham w/V4P

*V4P = 7,000 lb. trailer towing package... look for a hitch

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From Seventy nine.


1977-1996.