Redman is correct:
"Cylinder deactivation, standard on the 5.7, was left off the 6.1 because it didn't work with the lumpy cam profiles. Hence, the impending gas-guzzler tax." - Car and Driver February 2005
http://caranddriver.com/article.asp?...age_num ber=1
"As part of the engine upgrades, its Hemi lost the multi-displacement system that allows its standard sibling to cruise in 4-cylinder mode." - Road and Track February 2005
http://www.roadandtrack.com/article....age_numb er=1