I don’t really have one.
Not without seeing what happens without it.
The only heads I see with any type of regularity that have the vane are AFR SBC heads.
The few I have bothered to flow have come up short compared to the advertised numbers(numbers back up at higher lifts).
Over on Speed Talk there was some discussion about the vanes, and as I recall Larry Meaux commented something to the effect of he usually removes them.
As I have commented before, “by looking at them”, I never would have thought the TF190 heads would flow what they do.
