Here is a good used set of 4.10's for a 10 bolt rear. These are for a 7.5" series 3 carrier. I bought them thinking they were for a 8.5"...I cant use them. Here is a link to the origional post that has pics. $80 + shipping.
http://www.thirdgen.org/techboard/en...-10-gears.html

 

~~~~~sold~~~~~~~~