hello i'm evans. i have some question about flowbench. how much CFM is the best for B20B with b16 head? can you post your flowbench chart? thanks for your help.

 

The rule of thumb is bigger numbers are better. That assumes that you put thought into the port design, not just hogged it out like some people have done. I think b16 heads generally flow ~230cfm, and most simple port jobs bump that up past 260cfm, up to low 300's. I'm not sure @lift those numbers were taken, but thats the general increases you'll see.