I put a 2.75 third member behind the little 240 6-banger in my '68 swb It's a 3rd truck so I knew I'd probably never pull anything with it, (well maybe the silverado when it broke down ) I'm not a 6cyl fan but I have to say that I was really impressed at how good it pulled itself down the road. A hotrod by no means but it had plenty of "lugging torque" at cruising speed.
"Be more concerned with your character than your reputation, because your character is what you really are, while your reputation is merely what others think you are."
— John Wooden
I am running 3.25's in my 71 right now and thinking seriously about going back to the 3.0's when I feel up to the task.
I am running a 9" though. My question is why use such a heavy duty rear end in an F100? Drop a 9" in there and have all kinds of gear choices.
I love the low ratios behind a torque engine like the 460. It is like a gorilla on a 10 speed. He can start out in 10th gear and really take off without having to peddle so fast you can't see his legs.
clint