1987 F150 XLT Lariat rear axle code
You need more than that - there are several more numbers on the tag. If you can post the axle code on the door jamb sticker, we can at least tell you what ratio it is and whether it's LS or not.
If you happen to have the owner's manual it will tell you based off the axle code on the door. I have a 89 f150 with an axle code of 19. That's 3.55 gears with no limited slip. It was all listed in my manual.





