"Ls1 rear disc brakes" was how I bought mine years ago off eBay . If i had to do it again today I'd just call yards local and go pick off whats needed in person .
http://cgi.ebay.com/ebaymotors/LS1-...rQ5fTruckQ5fPartsQ5fAccessories#ht_1367wt_893
offer 170 under 200 shipped