sparafucile17

Ok, here's what I know so far: The engine is a 305 so the oem rear was a 2.73:1 and is, of course, a 10-bolt. But what is the spline count and ring diameter?

I've researched this a little and have been getting conflicting information. It's either a spline count of 28 or 30, and the ring diameter is either 7.5" or 8.5" (I think )

Does anyone who has or had a '90 - '92 Camaro know for sure what the specs are?

Thanks,
Jeff

Dave89IROC

28 spline, 7.5" ring gear(actually 7.625, but thats just GM making things difficult)

89Vert

if you are looking at new gears, if you want higher then 3.23 you need a 3.23 and up carrier,

I'd look into finding a 3.27, 3.45, or 3.70 9 bolt if you are looking for an upgrade

matLT1

I disagree, completely. Gear manufacturers make gears that will fit both the 2 and three series carrier, there is no need to change the carrier just to get a numerically higher or lower gear. Also, the 9-bolt was in Camaros for just 2 years for a reason, its a POS. That wouldn't be an upgrade, it would be a downgrade.

89Vert

not a chance 9 bolt is a way better rear then a 10 bolt,

bigger ring gear, cone posi is 10 times better then clutch packs and is lighter, bearing caps are far closer to the ring gear making it way stronger, press on axle bearing, no c-clips, also they used it 5 years 85-89, and the best cars got it, the axle that replaced it was the dana 44

DarthIROC

While your right about the carriers, your completely wrong about the 9 bolt. The 9 bolt was substantially stronger than the 10 bolts.

That being said, i wouldnt bother swapping out an entire rear end for the mediocre upgrade to a 9 bolt. If your putting down too much power for an upgraded 10 bolt to handle just buy a moser 12 bolt unit and be done with it. IMO if your gonna go through the trouble of swapping and entire unit do it once, do it right and dont do it again.

sparafucile17

Thanks for the info guys. Yes I am looking to buy a 3 series carrier (3.23 and up) I know you can buy a "thicker" gear that will still work with the existing carrier but the guy at Reider Racing told me that they always have complaints about gear noise. Even when installed 100% correct.

So I've been keeping my eye on the eBay auctions to see if I can't find a decent differential for relatively cheap.

Also, on the note that I should just buy a Moser 12-bolt and be done with it... I wish that were the case! I've seen many people recommend the very same on other posts. The problem is that Mosers easily cost upwards of $2000. Rebuilding a 10-bolt on a budget (including carrier) is about $700. (free install from friend)

I, like many others, am on a tight budget. And while I would love the ease and durability of a complete 12-bolt, I simply can't drop that kinda cash. During the rebuld of my car I constantly find myself weighing the tradeoffs of performance vs. cost. It's maddening at some points! Sometime I daydream about what I'd do if money wasn't a fact. Ahhh... She'd be awesome!

Unfortunately until I break parts, I'm just gonna have to rebuild as much as I can. And this is likely to be one of those cases.

Jeff

quickchicken

after owning 2 9 bolts you couldnt give me another 10 bolt. the only reason my 83 has a 10 bolt is its tight and i road course/auto-x my cars. i have the rarer 3.45 ratio and with the beating iv put on it like i did with my 83 i killed 3 10s and still on the same 9 bolt in my 89.
miles (diffsolutions.com) has a 9 bolt behind his 427. thats saying alot. the 9 was rumord to be as strong as or stonger than the dana 44 and the only reason they quit production is they were so expensive.

DarthIROC

Well with your mods listed a 12 bolt would be a waste of money anway, a solid late model 10 bolt with the 7.6 ring gear should do just fine. If i remember orrectly though stay in the 3.~ range with the 10 bolt i think the gear gets thinner with the 4.10 units. I could be wrong though Ive been outta the game a couple years.

sparafucile17

Agreed. I haven't added all that much power as of yet. The Exhaust probably bought me about 30 - 40 hp (headers back) but that's about it. The 10-bolt should do me well until I drop in a new engine. Depending how crazy I go with the new motor, I should be able to get by with the improved 10-bolt. If it breaks at this point, then I'll look into upgrading rears.

One more question though... Can anyone tell me the difference between an Eaton Posi and an Auburn? The Eaton looks like it costs about $50 - $100 more and I can't figure out what benefits you get from the extra cash.

Is the Eaton more for 4x4 applications? Which would you buy if it was for a street car?

Thanks,
Jeff

Tru2Chevy

Doubtful that you got 40 hp from an exhuast....prolly no more than 20-25 if everything else is stock or close to stock.

Difference between the Eaton and Auburn are mainly brand names. Personally I prefer the Auburn Pro Series diffs. That's what is going in my Dana 44

- Justin

IROCThe5.7L

Correct. Good post! Atleast you educate yourself before spewing stuff out.