I had purchased a Van's cabin heat selector box kit and I thought I would assemble it today so I could continue laying out the firewall components. Wasn't sure exactly how much FW room I would need for the device so I assembled it and took measurements. I have the same device on my RV9 and it works quite well. When cabin heat is not selected, the box dumps the hot air out the bottom or side so the device should be mounted near the bottom center of the FW but should not interfere with the exhaust hanger tang and springs.
