I have a 2005 ford f150 4x4 and was wondering what is the best thing i can do to my truck for trail riding. the trails i will be going down our mostly two tracks but i have to be able to go through mud and cross rivers that go across the trails. but i need to keep the center of gravity low so i can still be able to take corners at a decent speed for when i'm racing the truck. i was thinking of  build like a prerunner but not sure how it would hold up to the mud pits
thanks for your help  

how deep is the water how sharp are the turns and what type of racing are you gonna do i have 6" suspension lift and go through pretty deep water and mud got 40" tsls and it is a good combination for what i do .  

how deep is the water how tight are the turns and what type racing are you talking about i have 6"suspension lift and 40"Tsls i dont have too many probs in the mud  

any where form 1 feet to 3 feet depending on how much rain we get down here in lausinia. I do a lot of offroad track racing where the turns are anyhwere form 30 to 60 degrees. i'm looking at running like a 35 inch tire  

Is this a gas or diesel powered truck? A diesel puts you are a big disadvantage here because of the extra weight up front (about 500 to 600 lbs)and its zero tolerance for accidental water ingestion too. (Extra weight is never a asset off road)  

is gas 5.4 L  

(sorry, I missed that it was a F150) I would go no bigger than 35 on those axles (33 would be better and more "bullet proof") Next you need to do something that every one seems to turn their nose up at or think it does not matter (but it does) Install some 4.56 gears with 33 or 4.88's with 35's and it will run good and not be a slug and OD will work well too. If you do not regear you may be back here in a year (give or take) asking about tranny problems. Do not let number scare you because with tires size and OD it will be just about right. Make no mistake, you cannot chip or tune out the drag and extra power needed with big tires which not only need more power to roll but also raise effective gear ratio, making it work even harder.  

Selectable lockers is what I would do. Atleast lock the front end up for starters. Also good winch 9000lb or better.