I have a 9 bolt out of an 88 irocz. The car had the tpi 350, oil cooler, and the alluminum drive shaft. I ran the rpo codes and none of them give what gears it has. It has G80 for sure and I can recheck if you need them. I know there is one more code referring to the the rear axle but I can't remember specifically. I just want to know if it has 3.23's or 3.45's. My iroc has the 10 bolt with disc brakes like the 9 bolt and it has 3.42's. Any info would be appreciated.
AlkyIROC
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Jun 5, 2026
An 88 IROC with 350 TPI will have 2.77 gears. If it has the G92 RPO code, it will have 3.27 gears.
I just went out to the garage and checked the console out of the 88 and it doesn't list G92 which really sux. I was hoping it had the 3.45's since it had all the other goodies. I would have figured it would have had at least the 3.27's since it had the alluminum driveshaft and even had an oil cooler. Thought that if they got all of that then it would have come with a good set of gears. Do you know where I can get a set of the 3.45's and about how much they will run? Or would it be better to get a posi for the 10 bolt. That was the whole reason for taking the 9 bolt out was because it had a posi in it and when I blew up the stock diff in my 10 bolt the only diff I could get my hands on was an open wheel.
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i dunno man, pop open the cover and check. i just recently got my hands on a 9 bolt and when i checked the rear i had 3.45's i was pretty stoaked. and i believe it came out an iroc. had the iron calipers so it had to have been 82-88. you also never know if someone beefed up the rear also..9 bolts dont come in 3.23 or 3.42's or 3.73's its 3.27 3.45 or 3.77's so on and so fourth.Originally Posted by 85irocz355tpi
I just went out to the garage and checked the console out of the 88 and it doesn't list G92 which really sux. I was hoping it had the 3.45's since it had all the other goodies. I would have figured it would have had at least the 3.27's since it had the alluminum driveshaft and even had an oil cooler. Thought that if they got all of that then it would have come with a good set of gears. Do you know where I can get a set of the 3.45's and about how much they will run? Or would it be better to get a posi for the 10 bolt. That was the whole reason for taking the 9 bolt out was because it had a posi in it and when I blew up the stock diff in my 10 bolt the only diff I could get my hands on was an open wheel.