Okay, And yes i know that the intake should be less than the outlet. I'm also building a Pitts S1 and it's cowl is a pain in as to make. The drawing is from early 1970 and no plastic parts availible. Have the same problem there but it's more aerodynamic there not a big flat sheet forcing the air around the cowl instead of in. Just my 0.02kr (same as your 2 cents)