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

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 a lot more hp at 6000 rpm’s.
Just so you can understand the context from a Chrysler equivalent perspective its making 2.23 HP per Cube with a 318 head on a 318 engine. You can get far more flow from a 318 head than 195 cfm.

I'm sure if the Robinson Crew wanted more air they could quite easily get it. Its USING ALL THE AIR ITS GETTING. Like I keep saying you can give an engine more air it doesn't mean it will USE it.