I just bought a Noss head and love it. I got 19cc domes and im at sealevel so i must
run atleast a 50/50 fuel mix.
in terms of your questions, i dont think ive ever heard of a ported head. the size of your
domes and elevation should determine your compression and fuel.
if you got to nossmachine.com and look under banshee heads at the very bottom will give you a compression chart. from what ive learned at sealevel anything 21cc and larger you can run pump gas, 20cc-19cc can run 50/50, and 18cc-lower full race. im sure opinions vary on this but i tend to worry about burning a hole in my piston so i play it safe :ninja: