I just got my 340 powered car back from the shop after a chassis dyno tune. It made 258 hp and 293 lbs torque. (air temp was 90* and 41% humidity) I was a bit disappointed at those numbers but the shop owner did a good job of explaining how much actual loss occurs between "crank HP" numbers and "real world" numbers to the rear wheels. He said that he's seen a lot of deflated egos from customers who thought their "mega" engine should be producing more HP after seeing the chassis dyno results. He went on to say that the "15% " loss on a chassis dyno is a myth and that the actual percentage can be much higher.