Thanks, this thing has quite a bit more zip than the 348 and seems like it uses a 1/4 of the fuel. I'm not going to check until the o2 sensors are in. Not that mileage is my biggest concern but kinda curious. It's a much quieter engine in the cab going down the road, but it doesn't have the rumble of the 348 out the pipes but that,s ok. It's a cookie cutter engine but the reason they make cookie cutters is because so many people love cookies