It's all about what ones definition of "power" and "better". Torque being equal, HP will always be higher in a V configuration than an inline engine. HP is a calculation based on RPM and the inline Cummins engine will never spin as fast as one of the other V8 diesels. Seat of the pants will always be less. However, the inline engine is going to have a more ideal torque band for pulling a load at various speeds. In addition, for a given "power" it's going to use less fuel. What this translates into is on a 10 minute pull the Powerstroke is going to get to the top of the hill 15 seconds faster, but use 20% more fuel doing it. The higher RPM will also mean in the long run the Powerstroke will wear out faster. So it all has to do with ones priority and their definition of "better". You can easily build a gas motor to beat both of them up the hill... but you'll never pass a gas station and the motor will have a fraction of the longevity.