car is '81, use to be a V6 until the 2nd to last owner put in the 327 and did a lot of other stuff, i dont know whether he changed out the rear end or not.
i've been trying to figure out what rear end i have. everything i heard for 2nd gens was to look on the front passenger side of the axel tube for the code...
i sanded, wire brushed, de-greased, scrapped, did everything and there is no number on the passenger or driver side, unless i cam completely blind. the only numbers i found were on the differential cover where the axel tubes go into. on the passenger side the number was GM - 29 or CM - 29. on the drivers side it has the numbers 1254333.
if none of those numbers help, is there any other way to find out what my gears are?
also, my car will redline, about 6500rmp, at about 35 - 40mph, tops out at around 115 - 120mph , trans is a th350.....any one have any guesses from that?
thanks for any help....Nathan

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'81 Custom Camaro
built up 327
th 350 w/ 2400rmp converter
hooker headers w/ american thunder dual exhaust
Z28 spoilers and 2.5" cowl hood

The code is stamped into the passenger side tube on the forward facing side.

You can't rely on that code because the gears might have been changed out during the life of the car.

To be 100% sure, you need to either pull the cover and count the teeth on the ring and pinion or if the gears are still original GM, the ring gear will be stamped with a number loike 41-10. 41 divided by 10 would be a 4.10 rear.

You can also get a pretty accurate estimate of your ratio by jacking up the car.

If you have a posi(both wheels turn the same way when you turn either of them), jack up both rear wheels and put the transmission in neutral. Turn either wheel one full turn while counting the number of turns the driveshaft makes.

If you don't have posi (opposite wheel turns in opposite direction of the wheel you are turning), jack up only one wheel. Turn the wheel remaining in the air two full turns and count the number of turns the driveshaft makes.

i did the jacking the tire off the ground and counting how many turns the driveshaft makes a few nights ago. i only did one full turn though and it was 1.3 - 1.4.....so then im guessing had i done it 2 turns then i'd have a 2.73, non posi?
thanks for the help Gary.

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'81 Custom Camaro
built up 327
th 350 w/ 2400rmp converter
hooker headers w/ american thunder dual exhaust
Z28 spoilers and 2.5" cowl hood

Based on your count- it seems you have roughly a 2.73 rear gear (about right for the 6 cylinder and 305 v8 cars) posi was an option- so it's pretty doubtful that a 6-cyl vehicle had one ordered with it (if you're going cheap on the engine- why would you spend extra ??? on other drivetrain parts, right?).