I agree with Steve.. I think the 472 will spool faster than stock even with the right tuning. I've pulled another duramax behind mine no problems. Just gotta watch when the converter locks thats all.
My argument for the 472 over the 366... Sure they can both make enough power to blow your shit sky high. But the 472 moves a lot higher volume of air. They just pull harder on top without sacrificing any spool time, and also adding durability over a 366.
IMO the 472 is one of the best DD setups out there.. Soon as I do my motor I am switching to a 475 or 480 single.