rear end

i was wondering the difference from a 10 bolt to a 12 bolt. and if you were to switch to 373 or 411 gears would you just switch the housing or would the entire axle need to be changed? thanks

First question What size engine?
Second question What type car?
If your going 4:11 you should run the 12 bolt

I don't even have a car yet I'm looking right now though. I just wanted to know if i bought a car with gears i didn't want, and wanted to switch to a gear for more torque, what i would have to do to switch the gears? just change the gears out of the housing, change the entire housing, or the entire rear axle?

You need to switch the gears only but if it has a 2:00-3:00 gear you may need to buy a richmand (thick) gear for the carrier in the car. if you are going to upgrade the 10 bolt you should make sure it is a posi now. or you can buy a posi unit and have it installed into the rear end. Difference in 10 and 12 bolt..... The 12 bolt is MUCH stronger and the axels are much stronger in the 12 bolt. Dont worry if you dont have a lot of HP and wont be using sticky tiers for the car the 10 bolt will hold up well enough.