I ordered these from summit, actually called in to order and talked with one of their techs and told them what I was looking for. I have the stock 10 bolt 7.5/7.625 rearend in my 87 Camaro, and am looking for some high performance gears. He recommended these, I also asked if I would need a new carrier for this set, he said "no." I have all the hardware, shims, bearings, all new installation kit as well. I was never too sure of the "no" answer I got, Does anybody know if I will need a new carrier? I'm getting close to putting these in.

 

3.90 is a 9-bolt gear set, IIRC, which means it won't fit a 10-bolt.

JamesC

 

http://www.summitracing.com/parts/mgr-g875390/overview/

Here it is, it says 10 bolt. At least it says 10 bolt. Am I reading it wrong? This is the part number I got, hopefully you're wrong because I don't wanna have to send them back!

 

My bad apparently. Are you running a series 3 carrier? Check the 10 FAQ sticky at the top of the page for more info.

JamesC

 

if you have 3.23, 3.42, or 3.73 gears now, 3-series gears will fit.
3.08 and lower is a 2 series carrier.

Nice choice of gears. They'll go great with the T56 when you tire of the TH350.

 

The first thing he should have asked you is what gears are in the rear end right now. This is one of the big reasons that I tell people NOT to buy rear end parts from Summit or Jeg's. All that they know is what is on the computer screen in front of them. They have no experience with rear ends and don't know what will work and what wont. I always recommend buying rear end parts from someone like Randy's Ring & Pinion, Tom's Differentials or DTS. These people work on rear ends every day and they know exactly what you need and what will work. And most of the time they have better prices and better quality parts than Summit and Jeg's.

Now if you have 3.23 or 3.42 gears right now then the 3.90 that you posted will fit the differential that you have. If you have a 3.08 to 2.14 gear then you are going to have to replace the differential with a 3 series.

 

I will look into the 3 series diff. My car's gears are currently the 2.73's that came with the carbureted automatic Z/28. Thanks for the info!

 

Ok, another question. Looking at my gears, they are 27 spline. My axles are 26 spline, and the series three carrier I'm looking at says it will accept 26 or 28 spline axles, do the gears being 27 spline still work? Will I need matching axles? I'm pretty good with the engine stuff, drivetrain not really my thing....yet, I'm learning. Can anybody answer that question for me?

 

That's 27 splines on the pinion shaft, not the axles. Completely different thing.

You can get the special thick gears that fit the 2 series differential. If the salesman at Summit knew crap about rear ends he would have told you that and got you the correct gears. Don't buy rear end parts from Summit and Jeg's.

 

As BGH said: 27 splines = pinion shaft.
The axles and the differential need to match 26 or 28 splines. 26 was up to 1989. 28 splines started in 1990. (+/- a year). You can use your existing axle shafts, and must match a new differential to it. Or, if wanting to upgrade / need to replaces a shaft, you could step up to the 28 spline shafts.

 

Noted. Thanks very much.