The mags (Pop. Mech, Trucks) have done comparisons in the past, and the bottom line is that for 6.8L vs 8.1L the V10 performs as well or better.

The 3 valve 6.8 should be even better. I'd like to see it included in a current comparison.

The GM has the Allison which is a plus. Is the Torqueshift available with the 6.8 this year?