Will my truck pull 31's without problems? It supposedly has 3.08 gears but it seems wound fairly tight at 60. Anything over 60 and it's screaming.
I have 15 x 8 wheels and am looking at 31's but worry about the gearing a little.

 

Yes, it'll "pull" 31's. The big six is a low RPM engine so doesn't need to wind to create torque.

Now, it might not pull a heavy trailer easily with 31's, but you didn't mention that. So, if you are just driving around it'll be fine.

 

My F150 with 4.9L engine turns ~1715 RPMs @ 60 mph with O.D. manual. Check my math, Gary, but in 3rd [direct], my truck would be turning ~2400 RPMs w/o the 0.71 OD.

On top of that, the C6 has slippage the manual does not.

 

It will spend it's life hauling tools. Not anything major heavy but always hauling. It would be nice to pull a trailer once in a while. I do have a newer 3/4 ton that I use when I haul tractors or anything heavy.
Right now I use a Toyota 4 banger for work but it just doesn't come close to doing what I need it to.
If I could find a decent deal I'd like to put a utility bed on the ole Ford.
I may re-think the 31's