What gear is your rear end? I have mine set up to split the gears so that I can actually shift into 6 forward gears, 1st under, 1st overdrive, 2nd under, 2nd overdrive, 3rd under, 3rd overdrive. I don't have the governor set up as that would preclude me from shifting into 1st overdrive which I do use occasionally. I also have a dash light set up to remind me NOT to start out with the truck in overdrive. You've seen the insides of the transmission's overdrive, you know why.
I have had this transmission in this configuration for 36 thousand miles and I am a daily driver year 'round. You will love the overdrive, especially if you have the 3.90 rear, as the math is (overdrive .70) X (3.90 rear end) = 2.73 final drive 3rd overdrive. Depending on your tire diameter you will be loping along at 2000 rpms at 70 mph. Make sure your brakes are up to it!!
