Yz-
I'll assume you have the Eaton style axle (big round cover on back), banjo style axle.
Look for a GM corporate 14 bolt full float axle at the local junk yard. They are common and you should be able to get the whole axle for around $100 or so. This is one tough axle... so it won't break, but you don't get a lot of ground clearance with it.
Alternatively if your in love with your axle and want to keep it, why not switch to disc brakes? You might be able to get some from Blackbirds Custom Trucks (
http://www.blackbirdscustomtrucks.com/ ). This will be more costly and you'll likely have to change your master cylinder as well.
If you get rid of your old axle, put it on the "For Sale" section of this site... someone might buy it from you and help offset the cost of the new axle.
