Last weekend,at our dyno meet, those of us seen Sled Puller make 557 HP/1257 TQ with a 180 smog pump truck(his truck was imported from out west) at our dyno run. I do realize the twins helped some,but,his pump other than the delivery valves and the cam plate is stock and he used the 370's in it. The rampant rumors are that you can not make 600hp on them and they drive bad along with idle rough,I have not seen it. The DD3's make 7hp less than the 370's according to my notes from a chat with them(DD) and have less smoke. This is a theory that does not make sense to me. Old tuners tale says-if there is no smoke in the chimney,there is no fire in the oven. Guess the debate will continue... ... . Andy