contingent upon signing of contracts my company may be purchasing 3 new trucks. 2005 3500GMC dump rackbody duramax(diesel) 2 -2005 ext. cab GMC Pickups undecided weather 2500hd or 3500. My question is about what size engine. The 6 liter or the 8. Same HP, and GMC site said same torque? I thought the reason for the 8 would be about torque. The 8 will eat more gas. I am thinking the 6 will be fine. Please correct me if I am wrong. I,m sure there is some reason for the 8. More info.- They will be 6 foot beds, they will have plows in the winter and a possibility of spreader. At some point they may tow 20' to 24' enclosed trailer. I know there are gurus out there that are gonna tear this one up.