What is better Chevy 427 or Chevy 454 engine?

Depends on what you are doing with it. If higher rpms are a requirement, then the 427, would be your motor. Road racing would be an example of needed higher rpms. The 454 wont rev as high, however, makes much more torque. Drag racing, towing, off road, ect. From the factory, if you compare the two top contenders from each, the ZL1, 427, verses the LS-7, 454, they both made about the same power. I would have to mention that the 454 is making the same power, at a lower rpm. Some would say it is not working as hard, being larger, thus being easier on the motor. But, the arc of the horsepower curve is at its best when rpms are higher, which the 427 is more capable of. The 454 would have the edge, when it comes to stroking a mountain motor out of it. But, there were not many 427's made. Though I love the 427, I would go with the 454, personally. More power, with less effort, means less money. Also, 454 parts are everywhere. 427 stuff interchanges a little bit with 396 stuff, but, not at all with 454, so the parts are harder to find, and more expensive. Also, to make the 427 run, you need the bigger heads. Closed chamber, rectangular port. Try to find a set of those. The 454 will run good with the smaller, open chamber, oval port.