What car came with a posi rear?

[utfan01ss]

I have a 85 cutlass I'm installing a 450hp SBC motor in but need to find a posi rear end to go with it. This is not a dedicated drag car so I don't need a 12 bolt, owning a LS1 camaro I know all about the weak 10 bolt rears. Anway is there a car I can find in a junk yard that came factory with a posi rear that will bolt right up to my cutlass? Thanks

 

[bigdan]

unless you have an original 442 8.5" 10 bolt diff , forget about the original 7.5" 10 bolts that were in most g body ...
with 450hp ,all the money that you would invest in a 7.5" will be wasted .

even if some here will say the oposite ...

if on a thight budget and dont care about differnt offset wheels , go for a 9C1 8.5" posi with 3:08 gears & disc brakes : cheap ,strong 31 splines axles... and needs only special 179.00 offset uppe arms to fit and 6.5" back spacing rear wheels .....

if cash is no matter go for a used beaten GN diff that you will invest $800.00 to refurbish (beside the $900.00 initial buy) or a g body modified ford 9" from any manufacturer like currie or...
Dan

 

[Stoopud]

You seem to know that the 7.5" is not strong enough, but do not have the cash to do better. I fully understand, I am in the same boat. Don't put too good of tires on it and don't hit it too hard and you may be able to make it last(?)

Try to check s-10's and f-body's of the same vintage. The housings are different but the carriers will be the same. You have to make sure it is of the same vintage, because the changed the splines in 85-86+/-. I have also been told that some of the wagons were posi, but when was the last time you saw one of those in a junk yard? S-10's are probably the best bet for availability.

Does anyone know if the diesel G's had 8.5"? Someone told me once that they did but I have never been able to find one to check (I was told this right after seeing one in a yard but it was gone when I went back). Just curious, it would seem that these guys would be less likely to know what they have and may let one go cheaper.

 

[IrvJr]

Most 8.5's out of the GN's arent beat and in need of refurbishing. Those can stand up to alot of punishmnet and last quite awhile. I say find one in good working order and run with it.

 

[Blake442]

Diesel cars had 7.5's just like everything else.

Once again, the ONLY cars that recieved 8.5" axles from the factory are:
'84 Hurst/Olds
'85-'87 Olds 442
'84-'87 Turbo Buicks

That's it, no Montes, no Pontiacs, nothing other than those listed above.

And 'Posi-traction', or 'Limited Slip' was optional on every G-body car.
Look for RPO code G80, or look for the aluminum tag on the rear cover.

 

[bigdan]

IrvJr ,
ok lets admit it`s been own by a pastor ....he will still want clse to a $1000
for it so ..not worth beside a brand new currie 9 " for around $1300

my point is : the price are so high for these used GN 8.5" that unless you get a good price on it it aint worth the move ..they never had 31 splines either

 

[jrm81bu]

Not picking here, but where are you getting a brand new Currie 9" for 1300 at?

 

[bigdan]

on ebay there is a old currie employee that owns a shop
sells the same hsg ,axles, gears complete for 1300

hsg+ axles (moser) 650.00 so : cheaper if you alredy have a center section + gears at home .

seriously hose GN diffs are ok but nothng to go crazy for !

people pay up to $1000.00 for a used one ...no way it`s worth that $$$

 

[85GPLef41]

On the 9C1 on rears.. where can you get the upper control arms? Also whats the selection on the rims like? I know the bolt pattern is different but thats minor. Reason why i am interested there is a cop car sitting in the junkyard right now. Also there is a 85 El Camino with a aluminum tag indicating its a posi. The yard wants the same for the posi unit as for the the 9C1 rear.. go figure. Would the posi be set up for 26 splines? I would like to put 28 splines if possible as i want it to be as strong as possible. If i use the 9C1 rear i could possibly do the 12 inch brake upgrade and match the bolt pattern?? I already got the spindles out of a Pontiac Parisenne that i plan on using as soon as i get the a-arms.

 

[jrm81bu]

on ebay there is a old currie employee that owns a shop
sells the same hsg ,axles, gears complete for 1300

hsg+ axles (moser) 650.00 so : cheaper if you alredy have a center section + gears at home .

seriously hose GN diffs are ok but nothng to go crazy for !

people pay up to $1000.00 for a used one ...no way it`s worth that $$$[/quote

Are you talking about quick performance?