I replaced mine with an Atwood 10 gallon, electric/gas combo unit. It fit in the hole exactly, but I had to move the vent up and over, (to match the opening in the original door)which required some drilling and repositioning. I also took the original stainless door and riveted it to the new heater. This also requires moving and riveting the spring latches. I got a "pull out" heater that was brand new for $269.00, from Sands RV in Madison, Ohio.
2003 GMC 2500HD 4X4 D/A Ext. Cab
Propane Powered Honda EU2000i
Lots of Hot Sauce!
Air # 283