What am I looking at?

[Fords4ever]

Not to sound too awfully dumb, I am pulling this from the rear tag on my 92 ranger differential. I am looking to find a 7.5 with 3.73gears in a posi trac and have read so many posts that list 8.8 that I's concerned if I am reading mine correctly.

Top Number 3900
Bottom # 73A 75 6A16

 

[merace19]

Missing a number on the bottom. 3.73 and 7.5 rear.

 

[86 slo-vo]

if its a l/s it wil say 3L73 75

 

[bcost882]

yea you hav 3.73s but dirt and rust sometimes the bolt hide the first one if it has a open space then 73 sorry no l/s. and people talk about the 8.8 so much cause they figure if they are goin to do a l/s the should put in slight extra work and put an 8.8 in the truck

 

[Fords4ever]

Thanks for the answers..I was not positive. From reading this, then it is my understanding you can swap out the 7.5 to 8.8's to upgrade the overal performance?

 

[merace19]

For what purpose do you need to improve performance?