I got a fellow over here who has an '88 5.7 Camarao with the following VIN:

1G1FP2183JL140249

Did this model car come with the 3.42 rear end gears? Can this be determined from the VIN?

 

The VIN number will not tell your the diff gears. A 1988 with a 350 TPI has 2 gear choices. This car was only available with the 700R4 tranny and BW 9 bolt diff. The standard gear set is 2.77 and the optional G92 gear set is 3.27

 

Thanks Stephen.

If I see the G92 RPO code then I can assume it is a 3.27?

 

yes.

You can also look under the car to see if it still has a 9 bolt diff. Count the cover bolts or just look for the big rubber plug on the diff cover. If someone has swapped the diff and it has a 10 bolt, then you'll need to pull the cover and count the teeth. The chance of someone changing out the 9 bolt gears to a different ratio is possible but slim.

 

Thanks again.

This one is claimed to be a 10 bolt posi, That makes it a 2.77 if it is the orginal, right? Was it a posi too?

 

Ive also wondered how to tell if its a posi or limited slip, Ive checked the rpo codes and all it tells me is posi/limited slip, is there another way besides putting down some rubber on the pavement

 

Good question.

 

Jack the rear wheels off the ground and spin the pass side tire, if the other wheel spins in the same direction you have a posi. If it doesn't you have a fried one or none..

If you have a working posi and a friend with you.. have him try to hold the other tire still. You can kind of guess on how much life is still in your posi as to how much he can keep that tire from moving when you are spinning the pass side one. (don't think this works on G80 rears or auto lockers)

Or.... go do some smoky burn outs and count the strips.
ah hell go do some etherway

 

If the car has a 10 bolt under it then it's not original. The 2.77 and 3.27 are for a 9 bolt. If the car has a 10 bolt then the RPO codes mean nothing. You'll have to pull the cover to inspect what's inside.

 

My recently sold 89 Formula 350 was all original and had the G92/G80 package with a factory 10 bolt disc rear with 3:23 gears and PBR brakes. Don't know if the Camaros were the same or offered as such. In addition my buddys 89 GTA(350/G92) has a 9 bolt with 3:27 gears. So best thing is to crawl under and look. The G92 rpo may not determine the type of rear or gear. Also the gear ratio should be in your RPO codes(as an RPO) .

 

That's interesting considering 3.23 were not offered on any 89 models but they were in 1990. It's possible the 1989 was a late in the year production and should have been considered a 1990 model. That would have made it one of those 28 spline axle 1989 cars.