Chris, As I said earlier I am out of ideas without being there. I never found the type of valve made any difference and it still sounds to me like your heater is running with way too much air in the mix given the jet engine sound.
Steve
Steve and Andra
2012 F350 6.2 gasser SRW LB
Fab Fours front and rear in case we run into a rhino
2019 Northstar Laredo SC
