................ rather than just giving the dude stupid answers.

lets compare say, the p72 B18C head to that of the B16A


OK, so as you can see, the amount of airflow difference is minimal (and thats a p72 B18C2 head vs a pr3 B16 head) But you gotta wonder if the heads are tested on a flowbench.

check this site out to give you real specifics..

if you just throw a B16 head on a B18C you'll lose compression.

http://www.zealautowerks.com/