Cowl Inlet Door
I had the same problem years ago and solved it with a variable inlet. I live in Dallas and summer time climbs were brutal, but later, cruise temps were too cold. I have a NACA scoop on the bottom though. Heres a drawing of what I did 18years ago.... By the way if in cruise, and your cylinders are too cold, your openings are too large.
EAA Tech and Flt Advisor