Hello, I am new on the board. Just bought my Camaro, 1991, 350 Goodwrench (swaped, originaly was 305), manual world class T5 (broked in). Just some questions regarding transmission: 1. what series of carrier is installed in camaro 1991, 2nd or 3rd? 2. If I go for higher gears should I buy ring and pinion set 3.73 or 4.01? What is it OEM installed, 3.42 or? 3. Is it any type of OEM posi installed or just open differential? 4. If it is open is it better to install limited slip or total locker? 5. what count of spline it is on pinion I supose - 27 or 28? Thank You in advance for the help.

 

A 1991 with a 305 and M5 originally has 3.08 gears. If it has the G92 option code, it will have 3.42 gears. At least that's what was originally in the car. Since it's 16 years old and the engine has already been replaced, there's no telling exactly what's in the diff. Pull the cover, count the teeth, see if it's a posi or not and put in new oil.

The 7.5" 10 bolt pinion size is all the same. Your 91 diff will have 28 spline axles.

 

If the car has dual cats and the 2 3/4" exhaust, it'll have the 3.42 3-series rear end, and should have disc brakes, too. If it has a single cat, the 2 1/4" exhaust and drum brakes, it the 3.08 2-series rear end.

You said Camaro, but didnt say Z28, so I'm guessing its the TBI V8? That'll have the 3.08 gears, open (non-posi) 2-series differential.

 

It's TBI right, 350, rear drum brakes, but exhaust system is allready replaced by 3 inch Flowmaster. I just bought the car with such options. This one:

http://cgi.ebay.com/ebaymotors/ws/eB...m=290162200393

It is still on it's way from USA. I hope next week I get it and I'll check out.
As I understood I must open the cover anyway to see if it's something done.

In case it is 3.42 should I go for 3.73? Will it be Ok with manual gearbox?
As I heard 350 engines are not compatible with manual gearbox as these engines provide bigger torque than 305 engines. Is this bullshit I heard?

Sorry guys for such many questions, this is first car I'm going to built up. All my life I customized superbikes, so I thought this could be something different for me. I allways liked Camaros of thirdgen, so I went with this one .

 

And one more question: If I go for higher is this right thing should I buy? http://cgi.ebay.com/ebaymotors/ws/eB...187612418&rd=1 The price seems to be Ok. And If I go for 4.10 or it is allready too much?

 

No.

It's an Eaton Gov-Lock. The worst kind of garbage. Commonly called, by the people who have the trucks it came out of, as the Grenade-Lock. And even they HATE it because it's so terrible; weak, unpredictable, and famous for shattering into a million pieces.

That ISN'T a posi, and it ISN'T a "locker". What it is, is an open diff just like what you've got, until the difference in RPMs between the 2 axles reaches some preset value (about 150 RPM IIRC), as determined by 2 little weights that you can see on those 2 pins in the carrier window; at which point the little weights make it suddenly lock up with a bang.

In other words, it has NO POSI ACTION WHATSEOVER until AFTER your tires are ALREADY spinning.

They will not survive long on pavement behind an engine that's any more powerful than what they came with, which was a 2.8L 6-cyl.

There is not enough difference between 3.42 and 3.73 gears to make the swap worthwhile.

The T-5 will be fine with the 350, as long as you treat it gently; no speed-shifting, and no dumping the clutch with the engine at high RPMs, especially with sticky tires. You can tear that trans up with a 6-cyl, or you can make it live a LONG time behind a far more powerful engine than some weak TBI 350. It's all in how you drive it.

 

Thank You, saved my money And when I open diff cover how to recognize what size of gear is it, I mean should I count rings teeth or it is stamped anywhere 3.73 or?

 

I contacted seller of the car, him told me it is not mdified rear end, so I suppose I have 3.08.
So if my rearend has gear 3.08 should I go for 3.73 or 4.1 ? Anyway I'll open the cover to install Auburn posi.