muteboy49

84 camaros had the 8.5 inch 10 bolt right? 28 spline?
i need to buy a spool and all they had under 8.5 inch rear ends was 28 spline

84 Z-28 350

7.5"/7.625" 26 spline

Sonix

iTrader: (1)

8.5" is for 2nd gens, and other GMs.

Don't you have a street car? I don't think you really want a spool..

muteboy49

thanks. yeah its gonna be a "street/strip" car but it wont see much street use. just to work and back and maybe an occasional trip out to school and back

AlkyIROC

There are no spools for the 7.5/7.625" diff. A mini spool for 26 spline is available but it's designed for dirt track racing.

The 7.5" diff isn't a performance diff so performance parts are non existant or very hard to find and expensive.

No third gen ever came with a 10 bolt 8.5" diff and no other factory diff from anything other than a third/fourth gen will be a direct fit.

Factory options are

10 bolt 7.5/7.625" diff. 26 spline axles up to 89. 28 splines after 1989. Fourth gen diffs are a direct bolt in and are identical to the late model third gens except they're about 2" wider on each side

7.75" 9 bolt diffs are stronger but if you do find one, performance parts are even harder to find and more expensive.

SLP Firehawks had them and they were once available from the GMPP catalog but the strongest factory diff available was a 8.5" Dana 44.

Identification between the 3 is easy just by looking at the rear cover. 10 bolt has 10 bolts on the cover and it's smooth. 9 bolt has 9 bolts on the cover and has a rubber fill plug. Dana 44 has 10 bolts on the cover and has a metal fill plug.

Aftermarket options are a 12 bolt or 9" and each would set you back about $2500 for a complete bolt in diff.

Install a good posi in the diff and drive it. If you ever break the diff, consider how much it will cost to upgrade at that time.

Rosco the Iroc

On the 3rd gen 10 bolts, I have a '91 Z28 with G65. What kind of axles are in it? Does drum or disc matter for how long they are?

91drag

i got a full spool in my 91 camaro that i got from a friend ill ask him where he go it and let you know

Sonix

iTrader: (1)

rosco,
you have 28 spline axles, since it's post '89. Drum and disc shouldn't matter on the length.

Rosco the Iroc

Where do I measure to see if it's
a 7.5 or 7.625. I need a set of axles and I just want to be sure of what to order.

Ricktpi

7.50 or 7.65 take the same axles, the spline count is what matters. BTW G65 is not a valid RPO code for 3rd Gen. It is for self leveling suspension on 00-06 cars

D's89IROCZ

Maybe he ment G-92? Wasn't that the code for the 9 bolt rear ?

sofakingdom

iTrader: (1)

No.

Rosco the Iroc

ooops- Yea I ment G92.
http://photobucket.com/albums/v101/R...urrent=RPO.jpg

sofakingdom

iTrader: (1)

No.

G92 meant "performance gear ratio", along with assorted other things in various years. It didn't even mean a specific gear ratio, it just meant an "upgraded" one, whatever that might happen to mean to the particular car it was being applied to.

In the years that the 9-bolt was available, lots of cars without G92 got it. In years that didn't have the 9-bolt at all, G92 cars didn't get it {surprise} just like non-G92 didn't get it.

Rosco the Iroc

Anyway I'll prove if your right this weekend when I install a set of axles out of a '91 Firebird and they fit. They were a bargin $36 at my local salvage yard.

streetphase.com

does anyone sell the ring and pinion installation kits for the 7.5" with 26 spline axles? i can only find ones for 27 spline on summit... does it matter?

Sonix

iTrader: (1)

27 spline? That's for a different rear, 8.5" or something I think.

Many places have a kit, I'm pretty sure Ratech has one, probably the other big guys, Richmond, etc...
Go to their website, find the p/n (or phone them), then punch that p/n into summit.
ps. use a solid pinion spacer instead of a crush sleeve.

sofakingdom

iTrader: (1)

27 is the spline count on the pinion gear in a 7½" rear.

All years.

It has nothing whatsoever to do with the axle spline count.

The install kit is the same for all axle splines. The only difference, is 81-up rears use a different pinion head bearing (the big one) from 78-80. So it doesn't affect the install kit you'll find by looking one up by year for one of these cars since they're all 80-up. Only if you try to look it up strictly by axle model; then you'll come up with 2 possible numbers.