All this comparing your doing between heads 670...46...6X Is kind of senseless.
The cam is going to be the determining factor. You know like what rpms what cross sectional area you need for piston speed to achieve that rpm. Were itís going to make torque, convertor gear ratio. Itís like you canít arbitrarily pick a flow number.
The things they hide, the way they spin things, the excuses that they make and the things they omit.