My ? is that I noticed that my stock Exaust manifold has a 2.25 inch outlet I think and the Bonez race pipe is like 2.5 inches wich means the exaust gas is going from a smaller hole into a larger hole really close to the engine , wich I guess means less scavenging or gas velocity right???

But then again if theirs ever gas being sucked back up the little lip will stop the flow by alot right???

What R some of the effects of this?