Rear end-trying to get my tires to hook
 

i have an 86 monte carlo ls. I threw a 350 sb in it that i found dirt cheap. To my amazement it actually has some work done to it. The problem is i cant get the tires to hook up as it has an open rear. Are the rears that came stock any good? Should i concider a locker? Or should i just get a rear out of another vehicle, if so what type of rear and what vehicle(s) should i get it from?
Any input would be great!