315/75/16 are a very tight fit without a lift. I'm running a set on a 99 F250LD (7700) on a 16X8 wheel and besides the clearance issues you will lose a good bit of engine performance. I have 3.73 gears and noticed it immediately, i had 305/70/16 on before and should have stayed with that size. The 305's with the right wheel fit very nice

 

ive never seen and f 150 with 8 hole rims on it. so that truck probly isnt stock. maybe its just an option on the 7700.

 

If that truck is a 7700 package, it should have 7-lug wheels. Yes, 35's will fit. I test fitted a 35" tire just the other day. It fit okay, probably would have rubbed a little though. I just didn't like the way it looked. On top of that, it would have lost a good amount of power. I ended up going with the 33's and love the new look on a stock height truck. I did notice some loss in pep even with the 285's, so it would have been too much with 315's anyway. I'm getting new wheels soon just to push the tires out even with the fenders, but I'm happy with the tire size. I'll get pics up soon...

 

IF YOU ARE GOING FOR 315'S AND YOU DONTWANT TO SHELL OUT FOR SUSPENSION LIFT
THEY WILL FIT WITH A BODY LIFT I JUST ORDERED A SET OF 315/75/16
M/T'S ON 16X8 WHEELS
A FREIND OF MINE HAS SAME YEAR TRUCK AND HE IS RUNNING THE SAME SETUP WITH NO PROBLEMS OTHER THAN THE GEARING ISSUE
opps sorry about caps didnt realize they where on
just my .02
sparky