Thats bull about torque. The 6.4 was engineered to produced more torque down low because although its first iteration made like 500hp it didnt feel much stronger than the 6.1. Thats when the variable length runner intake came into play. SO now the 6.4 "feels" stronger in the 4300lb land barges they put them in. Yeah im pretty sure torque was at the top of the list with 6.4, even though the ports dont support that.