Aluminium v cast iron cylinder head

[shane]

Hi

What are the advantages over the aluminum head over a cast iron on a high-performance engine?

Is it just weight or are there thermal advantages with aluminum?

Are the new aluminum heads better for gas flow? 

Can a standard iron head be modified to give equal performance to the aluminum head?

Sorry for the long list but I am trying to use modified original parts where possible but not at a significant performance disadvantage.

Best Wishes

Shane