Rear End Fitment

[PropKat44]

I might be able to aquire a 12 bolt posi rear from a '70 GTO and was wondering what I had to do to fit it.

Is it a direct fit? ... I also plan on getting new trailing arms as well so....

 

[mrapii]

Need upper control arms, shortened driveshaft and probably wheels with increased backspacing.

 

[PropKat44]

Damn thats entirely too much for a quick inexpensive upgrade

 

[mrapii]

Is that a Turbo Regal? What year is it. All Turbo Regals from 1984 on had 8.5" 10-bolts which are plenty strong.

 

[PropKat44]

Nope, its a Regal T Limited ... (Blackout Trim, Alloy Rims, Heavy suspension, bucket seats and sport steering wheel, T trim)

Sadly its came with an Olds 307ci, 200 4r and a 10 bolt 7.5in rear with a sissy 2.56:1 rear end.

Ive upgraded to a non emissions equipped 305 with ported and polished heads, a mild cam, headers, a 600 cfm Holley with a edlebrock performer intake. I also put in a TH350 w/ a beefier final drive. Last but not least im in the market for a better ratio rear, Ive been pricing better gears, carriers, lockers ... or finding a 3.73 posi already together (needle in a haystack)

 

[pontiacgp]

sissy 2.56:1 rear end.

I have a 241 rear and although I plan on changing it there is nothing sissy about those gear ratios when your out on the highway.....

 

[betsy84]

Oh do I know it. I get the same gas milage to my cottage as my Honda does. 2.29s :wink: But that wont last.. 3.23:1 and posi coming before it comes out of storage from winter.

 

[betsy84]

Ive upgraded to a non emissions equipped 305 blahblah

I'd just throw a new set in the 7.5". Box the lower arms, get UMI LCA relocation brackets, and you should be fine. The 7.5" 10 bolt can take quite a beating, and with only a semi built 305, it should last for a while. Unless you do burnouts all the time, or have sticky tires and alot of tq, you should be fine for quite a while.

 

[PropKat44]

Ive actually been considering that... pricing out the insides of the 7.5" with a locker isnt too bad

 

[Chevyman85]

I'd get a hold of a 8.5" out of a GN, That'll be your cheapest bet. I spent $1200 of my 7.5" to buld it up...