How can I tell what type of gears I have?

[jgrisafi]

I need to make sure that the gears I have will hold up to 420hp and 400ftlbs of torque. Does anyone know the best way to tell which gears are which. I included a few pics of mine. Thank for the help guys.

[N2TRUX]

I'm not sure what you mean by "which gears are which". You have a 12 bolt axle, with an open carrier. That means you do not have any kind of locker, or posi-trac.

I see that you have a GM carrier, and it appears that the ring gear is GM as well. I can't see the numbers on the rng gear well enough to determine what ratio you have.

What transmission will you be running? What rear tire height/width? This info will help give a better asnwer.

[jgrisafi]

If you could let me know where to look for the numbers you need please let me know. All I need to know is what gear set I have so I can either by the 3:73 I need or stick with what I have.

[jgrisafi]

I will be running a TH350, an sbc350 with about 400-420hp, 18x8front and 20x10rear.

[LONGHAIR]

The numbers that are stamped onto the edge of the ring gear (in the 3rd pic you posted) will tell us the gear ratio.

As far as "changing them", I certainly wouldn't use the ones you posted in pic #4 as replacements. Not only are the obviously abused, installing "used" gears is even more complicated than new ones. This is best left to a professional and very few of them will touch used gears anyway. It's just not worth the risk of failure. New gears are only $150-$200

[jgrisafi]

Thanks for the insight Longhair, I really do appreciate it. Asking this question really helped me out. As for the numbers on the ring gear, I will take a pic and get back with you. I'm just curious to know what the gears are. I guess I will just buy a new set of gears and be done with it. As for changing out the axles do you think it would be a wise decision to keep what I have, or buy new ones, depending on what shape there in of course? And Would it be a good idea to get a posi too?

[LONGHAIR]

Unless you really have a lot of power, the stock axles are ok. It starts to become an issue when you get a little more aggressive. Traction is the biggest factor. Bigger tires, traction aids, sticky surfaces like drag strips, etc. make up-grading more necessary.
As long as the bearing surfaces of your axles are in good shape, and you are not "dumping the clutch" on it, you should be ok.
Adding a "posi" unit will bump the price up by about $500....but if you intend to do it, the time is now. It won't cost you any extra as far as installation labor.