I need to upgrade to a stronger rear differential in my 85 pontiac Gran Prix. The 7.5 inch unit has limited days left.I've done a complete hochkiss suspention upgrade, front and rear. 12 inch brake conversion. I also have adjustable rear upper controll arms. The car currently has a 350 TPI with a paxton blower.

     I know the Buick grand nationals came with the stronger 8.5 inch 10 bolt, but this unit is hard to come by. Is there anything else I can pillage one of these rears from. Even if the thing is a little wider at the outsude of the drums that's ok because there isn't much clearance between the framerail and the rear tire to begin with. Any help will be greatly appreciated.

                             STU

The 8.5" axle (like in the t-Type and Grand National) is the same used in the B-body (full sized) except a shorter axle tube length.. you should be able to mix n' match to come up with a sweet rear for your 85 Prix.

If I had your 85 I would be sooo tempted to install a Lauren Engineering 2+2 front end on it.

    I wanted to do the 2+2 style, could not find any at the time. So I ended up reworking the existing fiberglass header panel and making a custom aluminum grill that has more rake. The final result ended up looking veryn similar to Richard Petties cup car of that era. I tried to upload a pic but this blastid thing is being difficult.

                                              STU

What is this lauren engineering you speak of? Is there a web site? I did a search, couldn't find anything. The factory offering is pretty rare, only about 200 or so build, of wich most of them went to race teams. I have only seen 3 examples so far.  

Check out this link, it will take you right to the Grand Prix area:
http://www.laureneng.com/page39.html  

If you get a chance, upload that foto of your car... I would like to see it.
As I mentioned on this site a couple of months ago, Pontiac would have had a big hit in the 80's if they took the notchback g-body and put the 2+2 nose on it, a 5.7 motor and call it the new GTO. I can't beleive they never did that. If I had the money I would build one like that with GTO emblems a powerfull motor and a 6-speed transmission! People would sure take a double-take, yaknow?!  

For some reason this thing won't let me upload any pictures. If you want you can see on the Myspace page I have. Just click on "view more pics" just under the pictire of me with the goofie hat on. Heres the url.

                           http://www.myspace.com/spooman77

you can get an 8.5 from gbodyparts.com  for a pretty decent price.  

I changed my mind I want to see more pictures of JOAN!!!!!!

ha-ha..

that is really on it's way to being a sweet ride! Keep yer CC buddies posted on the progress..

Ha ha, yeah she is quite the M.I.L.F.  Yeah Right now I'm doing some tweaking of the computer, so we can dial in everything with the supercharger. I'm actualy sending the whole ecm out to FAST tecnowlegies. I need to find the rearend first. Knowing the final gear ratio will help in order to properly dial in the fuel curve.

I will keep you posted.

STU