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n00b gots some questions

841 views 4 replies 4 participants last post by  Ghetto Jet 
#1 ·
i plan on changing my diffrental here real soon, using a manual i got at autozone. acording to the numbers i pulled of my diffrental im curently running a impressive 2:73(and everyone i talked to said it was a 3:08). useing the calculator on the web, with my 225/70/r14 and max RPM @ 6K this beast can do 185mph... yea like that will happon... in maybe 15mi of flat road. so needless to say yea, im gonna change it

what i have is a 76 camaro
327 @ a est 300hp @4.5K - 350ft-lbs @ 4K
THM-350
225/70/R14
and a 2:73 diffrental

from a post long past on here i asked what would be best to run and i got suggestions of 3:50 for a gear ratio, and talking to local people, my father, and my machinst friend they all suggest 3:73. playing with that calc on the web the diffrence between a 3:50 and a 3:73 doesn't seem like much, and realy, i can live with 125mph as my top speed. i live in a highly populated area so im never gonna be able to open it up to 125mph on the street anyway

what i plan to do is buy the parts to do the conversion, take it to a shop and have them install them, im told that posi are best for making a hot-rod, and grabbing good off the line power. and even worse i have had so many names for diffrantial types im abit confused, things like limited slip posi, full posi, and ofcorse normal stock 1 wheel smoker, and a few others.

so, what is the diffrence?
what all will i have to buy to convert my GM 10 bolt over to something better than my 1 wheel smoker?
and if anyone has had something like this done befor, a good price guess would also help(im dropping the axle myself)


help the n00b plz
Camaro76
 
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#2 ·
Posi-Positraction-Limited slip. All are the same thing they let one wheel over ride the other in corners and non spin use. Even the Locker type rears do this. Many variations on the same theme.

Now you are going to need a rear end installation kit. They are available at tranny-rear end shops, Summit, Jegs etc. These kits have side shims, pinion depth shims, crush sleeve, side and pinion bearings and seals. You will need a Posi unit of the correct series for your ring and pinion, ring and pinion,bolts, gaskets, rear end lube and sometimes posi lubeadditive.
 
#3 ·
thanks, that was quiet helpful to eliminat all that "i think i know what im talking about" garbage people try to feed me. and from looking on summit's site i see ring and pinions are about $200, and the install kit is about $100... so... which thing makes it a "posi"? im running a GM 10bolt, 8.5 inch... unknown spline count..... which brings me to the next question.... how would i find that out?
 
#4 ·
The pinion spline count is the #of splines behind the yoke that bolts in behind the driveshaft. The axle spline count is the # of splines on the ends of the axle where they slide into the carrier.

The thing that makes it the posi is the ~$600 piece. Often called 'the carrier'. The big thing in the center that the ring gear bolts to. it has the side gears, and the axles slide into it.

There are 2 or 3 different ones, and you want one to match your ring gear choice, like BOB said. I think the GM corporate 8.5 has one series carrier up to and including 3.08, and for anything numerically higher, you would need a different carrier. It might be 3.08 and higher.

If your car has the original rearend, it should be the GM corporate 8.5.
A 3.55 would be a little better on the highway than a 3.73, but a 3.73 will give you better launches, if you have the traction to back it up.
 
#5 ·
Your rear has 28 spline axles. The only thing you need to make your 8.5inch Corporate 10 bolt open rear have posi traction is to buy a posi unit, (Eaton make one of the best) and have it installed. As far as rear gears, it is my understanding that you can go from 2.73's to any gear thats available. Your going to have to have these parts installed by a professional, talk to them they will be able to give you all the specifics.

Mike
 
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