Sorry, No 6.4 Hemi for the HD's.
Dodge 5.7 Hemi- 390hp
Chevy 6.2 LTZ only- 403hp
Ford 5.4- 310hp
Toyota 5.7- 381hp
These are all 2010 numbers and the biggest gas engines offered in the 1/2 ton trucks. Only Chevy has more hp and that's only available in the top end LTZ model. The Dodge still pulls harder towing and rides the best, not to mention 0-60 times aren't too shabby.
On the MDS issue, most vehicles that I have either seen or driven my self achieve better gas mileage with MDS turned OFF compared to it operating. It might be different with the 09's/10's, but I doubt it. Most of the third gen guys report higher mileage with it off, and our 2008 Avie gets better mileage with it off as well.
Four cylinder mode on a 6,xxx pound truck just does not make sense.
Four cylinder mode on a 6,xxx pound truck just does not make sense.



