Interesting, Richard... I know the old Thunderbolts did quite well with 2-4" tubes... I'd still like to know what the tubes actually flow on a flow bench....
Once I have that number, then add in a cushion, I'll know how much other external air I'll have to pull from the cowl area.... Love that low pressure air at the base of the windshield....

Now if someone could just explain how there are so many EFI cars producing 400+ horse with just a single 3"-4" tube....???????

I'm not saying anything is right or wrong, just wondering what the actual flow number is......