SD,
I couldn't even get my Mega- mentals to the 600 range. But then again my motor has been tired for some time. Like I mentioned earlier it would be informative to know how much power a auto takes from a cummins diesel. I have heard several different views and you could actually do a real world test.

 

How much work is it to switch over an auto to a 6spd? I have ridden quads and dirtbikes all my life and when I hop into my truck I want to switch gears (especially since i have to turn off o/d when Im in town so it doesnt lug the engine going 60 k). Also there are so many problems I have heard with the auto transmissions, when I start to get more hp and torque, I dont really want to mess around with that..