I am going to chime is as a conscientious objector, aluminum heads make more power than iron heads in most (if not all) higher RPM applications, the weight loss is a bonus...The reason is heat transfer, iron heads, once hot, stay hot....Aluminum heads give their heat up very easily to the water so you can have the combustion chamber hot but don't have the excess heat in the rest of the head...What difference does it make you will ask next?

The intake side of the head stays way cooler than the exhaust side thus allowing little change in the air charge temperature, the colder the air charge, the denser the air (read more air to combine with fuel to generate more power). If aluminum heads don't make more power at higher RPM then why put them on any engine at all, how well do you think a Corvette would run with a set of late Vortec's VS> a set of D port aluminum heads?
Now on a different note, you brought up a supercharger, that takes everything I just said and throws it out the window, why you will ask next?

Because the air charge is being forced into the cylinder heads and while under pressure the density of the air charge will have little to no effect.........

So while you are right (a little) you are actually more wrong on a naturally aspirated deal (which most of us just happen to have...).
Welcome aboard, keep your Sabre at under 70 MPH, keep the HP reasonable on the quarter stringer deal, and more importantly have fun.
BTW that hull is heavy due to the fact that it is a quarter boat...The reason is a heavier layup to make up for the lack of the rigidity of the stringer structure....some would say built for comfort, not necessarily speed...

There are some of the coolest people on the planet on these boards (Ralph included) so a little respect can go a long way.....Just my opinion....(which means squat, but remember I said conscientious objector

)
GT