RV-6, O-320. Cabin heat muff inlet is on the aft, right, vertical baffle, thru a screen and into a 2” SCAT hose, the to an Aircraft Spruce Turbo Heat muff. (
https://www.aircraftspruce.com/catalog/eppages/turboheat05-15249.php?clickkey=80990). I have far more flow than I can even use or even modulate easily, but very very little heat. I taped off most of the inlet, which did nearly nothing. I’ll pack the muff with steel wool next but even that did very little on the old muff. I’m in southern California so cabin heat has not been a priority but now that we’re entering an unusually cold winter I may end up adding a second muff, plumbed in series to the existing one.