what do i need to change the gears in the front diff? do i need a new carrier or just a set of gears?

 

Depends on the ratios that you are starting with and what you are going too.

I changed one from 3.50 to 4.10 and had to change carrier assys.

Why are you only changing the front ratio?? You know truck won't move if ratio's front and rear don't match.

 

In a 1997 F-150, a set of reverse cut 8.8" gears and the appropriate installation kit.

 

are you going to do it yourself? if you are you need a micrometer to sheck the shim thickness and a paclash meter to check the ring and pinoin is in proper proamiters, R.P. is not a job for you oil change and tune up mackanics, if you do do it just make sure you follow the derections to the T hope this helps if you have any Q' about ring and pinion changes ask i have done a few,