Another guess the Dyno Numbers

Per Indy they flow 263 cfm @ .500.

Which was basically my point.
You don’t need heads flowing 263 to make 385hp.

That build isn’t going to show what LAX heads are capable of.

For lack of a better way of putting it...... they’re a bit “overkill” on a mild 360(IMO).
Sometimes when the heads are too much overkill, they can cost you power.
I’m saying, it doesn’t really look like they cost any power in this case.