I recently bought a 1986 Z28 and want to know what is the stock rear end, I recently counted 10 bolts on the differential and wanted to know if it was stock or aftermarket. Its the LG4 model. I planned on getting rear end rebuilt and adding 3:73 gears anyway. Thanks in advance

 

I don't believe it was stock, when I went searching to buy a 10 bolt, I had to get one off a 91-92 z28, but I could be wrong!

3.23 came stock in mine, and if you were going to rebuild it anyway sounds good to me!

 

Starting in '82 GM used the 7.5 inch 10 bolt rear end in all F body cars. Around '85 or '86 they started using the Borg Warner 9 bolt in the high performance models, but the rest continued to use the 7.5 10 bolt. The 9 bolt was discontinued in '89 and all F body cars got the 7.5 inch 10 bolt (upgraded to 7.6 in '86) until '02.

 

https://www.thirdgen.org/1986-chevy-camaro

In '86 the Z28 got the 10 bolt, the Iroc got the 9 bolt.

The '86 Z28 had 2.73, 3.23 and 3.73 gear options along with open and posi.

If your car is an auto trans it will be a 2.72 gear, if man. trans then a 3.23, and could have option of posi 3.73

 

Wow, great information to know.

I got my rear end out of a 92 Z28 5-speed does that mean it's either 3.23 or 3.73? The guy said he thinks it was a 3.23 but I haven't got it pulled apart yet.

 

If you got it out of a '92 then it has 28 spline axles instead of 26.

 

If my memory is correct you may have a 3.42 gear I think it was an option after the 3.45 Borg Warner rear was discontinued.

 

https://www.thirdgen.org/1992-chevy-camaro

Every year seemed to be different

'92 Z28 had options of 2.73, 3.08, 3.23, 3.42

 

IIRC, 3.73's died with the L69 in 85 or 86.

JamesC

 

The '86 Z28 LB9 A/T was 2.73:1 or 3.23:1.
'86 Z28 LG4 A/T was 2.73:1 only.
'86 Z28 LG4 T5 was 3.23:1 only.
'86 Z28 L69 T5 was Players' Cup only, so you can't have one, but was 3.70:1 only.

 

My 86 Z28 LG4 came factory with 2.73:1 and is a factory T5. Best thing to do is check your rpo codes on center console lid.