i own a 91 s10 thats gonna get a mildly built 350 transplanted into it and was wondering what all could be done to beef up the stock rear end.  i know that if i baby it it would last for a little while but the way i drive its going to brake somthing  

Your best bet is to get a 8.5-inch ring gear 10-bolt from a Nova or Camaro and try to transplant that into your S-10.

Measure the widt of the 10-bolt in your S-10 now, from backing plate to backing plate, and from spring perch to spring perch. Try and find a rear as close to this as possible. More than likely you're gonna have to move the spring perches on whatever rear you find, but if you can find a rear that's within a 1/2" of your stock rear, you should be ok.