What would it take to make 1.44 lbs-ft per cid ?

Hysteric said

Don't conflate cylinder fill and efficient combustion with airflow. Here it is again because you seem to equate more airflow with usage:

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No, I’m saying it’s got most of what it can get out of these heads by 5000 rpm’s. If your building a 6500 rpm engine like this one it should be making a lot more hp at 6000 rpm’s.