I have a 99 f-250 Sd 5.4 5 speed manual with 35s and i am thinking about putting 4.88 gears in it, is it a little over kill?

 

I was thing that would be a good gear ratio also !

 

That would be about right for 38s. Running those gears with 35s will kill your hwy mileage. You should probably go with 4.30s or maybe 4.56s.

 

It's too much for my taste, but should have great acceleration. It all depends on your typical cruise speed and how many RPMS you want to turn doing it.

 

I did 4:88's with my F-250 with a v-10 and it was too much gear for the 35's wold have been perfect for 38's I would look at the 4:30 or 4:56, Yukon makes very good gears if you are also shopping for brand.... Good luck.

 

It's never enough until your heart stops beating.

 

I was running 4.88's with my 38's and now with my 41's makes a big difference with tires of that size but with smaller tires it would be a little much unless your drag racing....

 

4:30's w/ V10 are perfect with 33's (stockers). The will be VERY good with the 305/70/18's (35", BUT a wee bit wider than stock).

If I were to go with 325/65/18's (35" and fairly wider than stock) I'd still be happy with 4:30, but may think 4:56.

That's the limit...anything larger and it's 4:56 and up!