I have a 2007 F150 4x2 with a 4.6L motor. My plans are to purchase and install either an AF1 or K&N intake, and some SCT tunes from Troyer. Right now I am running the stock tire diameter (255/65/17). Once I wear out my stock tires, I plan on getting a set of 33" tall tires matched to my 17" rims. I am even considering going to a larger wheel diameter such as an 18" or 20", but no higher. If I do that, I would still like to keep the tire diameter around 33", but no higher than 35" tall.

Now, here is the issue at hand. I want to re-gear, but can't decide which gears to go with. Should I go with 4.10s or 4.30s (4.56s, I think would be overkill)? Any brands out there that you all would recommend? I'm leaning towards Motive Gear right now. Also, I want to have a posi installed, but don't which brand to go with. I had a Gleason posi on my '78 Monte Carlo back in the day, and had 0 problems with it. Any recommendations? Lastly, what diameter rear end do I have? I'm sure it's not an 8.8...is it a 9.75?

I do about 50/50 highway and in-town driving. I do plan to take the truck out hunting next year, and the area where I will be hunting is pretty moderate as far as the terrain is considered. Mostly bumpy dirt paths and little, if any, extreme areas where a 4x4 would be better suited. Also, I really don't do any towing, but should I tow a reasonably heavy load, I don't want the truck to flinch.

Please help!

 

What is your cuurent ratio?

Generally people are happy with:
33-inch = 4.10 (or 4.56 is you want more bite or tow)
35-inch = 4.56

 

3.55s non-LS according to the sticker on the driver's side door. I definitely want to steer clear of killing my overall gas mileage, but do realize my RPMs will be higher than now when I am driving on the highway. I seriously doubt I'd go with 35" tall tires anyways, but would it be safe to say that 4.30s would be a good compromise between 4.10s and 4.56s?

 

Yes, but if you stick with 33-inch tires, the jump from 3.55 to 4.10 may be pretty good as well.

In the end we're only talking about a couple percent difference.