[Michael C Henry]

I didn't get the sequence .The heads were produced for a particular purpose.They were done with the therory or knowlege of airflow and port design at that time.The story I have is the Canadian Super Cobra jet heads were supplied to only factory sponsered cars like 428 mustangs and fairlanes and were mostly a secret for the first year or two . The reason the factory cars were so much more dominate was descovered afterwards.