My 496 makes 1.23 hp/ci with a very mild hyd roller and 9.8 compression which is why I expected the 408 to do better. But, my 496 is the result of dozens of previous builds while the 408 was the first one of its type. I might have an opportunity to do another 400+ inch SB with the TF heads coming up. This next one would be for a bracket car so it would get a roller and a single plane and some more compression. Probably shoot for 600 on that build.