i was looking at some stamps on the head itself......one of them is a stamp that says PM3-3. on my friends si, his stamp says PM3-6. next to it is a stamp that says 8/8, which im guessing is the year of the motor, and more off to the right, another stamp that says 1/6, which i hope stands for the displacement. can anyone shine some light on my subject?? everyone else ive talked to cannot tell the difference between the heads....but someone has to know.
peace

 

from what I've been told, the only diference between the heads is the cam and valvesprings. So if you're going to swap them out anyway, it shouldn't matter.

 

Ive been told the only difference is the cam.. Thats all I am gonna change when i do the mpfi swap..