[cutlassefi]

Norm. how do you know the 425 won't rev quicker, not just in park or neutral. Can you prove it or is it your opinion? Do you have the facts to back up your statement? Have you run this very test yourself? Where is the written proof for your statement? And who wrote it?

In theory, all else being equal as you said, the 425 will have a slower piston speed and therefore should rev quicker, less reciprocating inertia. Whether or not it's measureable on this combination is a different story, althought that can be verified on a dyno now. It's called "rate of acceleration".