31 spline Ford trac lock??

I just got back from the junkyard and pulled the limited slip out of an 98 Mountaineer. Is the flange from the driveshaft different that mounts to the pinion gear?? Is it different from the flange than the one that is currently on the car?? I pulled the limited slip and the gears (3.73) and left the flange in the yard. Has anyone had any luck with this setup?? I only pulled this because it was so cheap and havent read up on this subject. The gears and limited slip for $25. Not too bad I suppose.

I dont currently have the axles, but its a back burner type project. I have a spare 8.8 in the garage. I need to get some rear disc brackets and calipers and will just change the rear as a unit. I just dont know too much about the 31 spline ford tac lock. I know its better than 28 spline, its durability has to be much of the same as the factory clutches.