[1G1YY]

I have a 68 12 Bolt diff running 3.08 gears and want to go up to 3.73. A guy has some 3.73 gears and "carrier" to suit for sale locally. The carrier is stamped 3866116. My rear is a 3 series and the carrier for sale I think is a 4 series. What I need to know is the 4 series carrier going to be compatible with my rear that has the 3 series components? Thanks for any assistance. Pete