Answer Tom, to convert back to natural gas the orifice assemblies would be needed as the NG orifices are not listed as separately available. They assemblies are as follows: Left front [WB28X20607], left rear [WB28X21953], center [WB28X21513], right rear [WB28X21954], and right front [WB28K10812], the gas valve [WB21X21506] and the broil tube [WB28X20389] would also need to be replaced for the NG orifice Read More... Answered by AppliancePartsPros.com | Tuesday, April 9, 2019