They should work in your diff. case, but 3:55's will not work on a 3:08 carrier. There are three different carriers used depending on ratio. Unfortunately 3:55 and 3:08's used different ones. I tried the swap many years ago (3:55 posi to 3:08 using the posi carrier) and there was not enough room to even install the gears. I had to locat a posi carrier for gear ranges between 2:56 and 3:23 to make it work. The FAQ section mentions three different cases depending on gear ratio, but I have found the difference to be in the carrier and not the case. I have a 3:55 posi carrier Ring and Pinion set that I may consider parting with. Good Luck
