Thats really cool to know, and very cool data! I have no issues with the airgap. I would love to do a comparison with a victor, and an airgap when we start playing with our new heads. Your data is a great point. It's funny, some engines just react differently than you'd expect. On a run of the mill 383 chevy, some guys wonder why we don't run a big ol airgap, instead of a "performer ish" dual plan, short rise. And in THAT case, for whatever reason, a low rise dual plane with no airgap, is within dyno variance. of an airgap, or even a single plane.
I remember testing air filters, playing around, and one of our customers really liked this little "stelling and helling" round air cleaner that was "famous" on old ford FE engines, especially in cobra kit cars. That green, lawnmower looking, foam filter, scrubbed something like 50 HP off of a 427 ford stroker, based on a windsor. i always enjoyed the engine masters series. And i admit i wasn't always right in my guesses. i remember buying new headers on a 318 car b/c they had a flat spot on the bottom.....then 20 years later i watch engine master smash tubes flat, and lose almost nothing .lol