Darin
Seeing as you are in the US of A I would suggest you get in contact with a suitably qualified gasfitter to this job for you, simply because if the water heater is not vented properly it will seriously cause havoc within the cylinders burning capabilities. Not only that you could well produce a poisonous gas – namely carbon monoxide which is a silent odorless killer that gets into a human,s bloodstream and will in a short space of time kill a human.
Do NOT much about or attempt a handyman kinda fix on any part of a gas appliance – gas can kill!!!
Selgas Services Ltd
Craftsman Gasfitters, Plumbers, Electrical Service Technicians