5.2/5.9 H.P build guesstimate

Probably not but there higher than an LA, compression matters, but unless were talking two or more cr points difference, were probably talking under 20 hp. The magnum head is were most of the hp gain is coming from.

Airflow is hp, lower cr is just gonna be slightly less efficient at turn that airflow into power. So you need more air and probably rpm to make similar power.
Agreed.
But I just think it is important to know not to trust published compression ratings when choosing other parts for a combo.