Billy, what RPM and speed are you cruising at with OD locked out?
I tow approx 5 times a year local to Indiana (up to a 4 hour trip). Once a year we plan to hit the smokeys or SC, so up to a 12 hour trip with mountain passes. Another thing to consider is I'll eventually up my tires a size to a 31.6 inch tire. I currently have a 30.5. That would drop the 3200 down to about 3100. I appreciate all of the responses.
Oddly enough I did a test and drove around with OD off for a while and averaged better fuel economy at the higher RPM range. It seems like the 4.6 gets better fuel economy revving. If I go through with it, I'll also have a detroit tru trac put in, bringing my bill to around 2000.00. So I'm just trying to weigh my options and see if its worth it.