I have never done a conversion, LP to natural gas or visa versa; but I do believe there are other things to consider such as orifice size just to name one. If you are doing a conversion make sure you understand exactly what you are doing.
"Clarity to Agreement" Dennis Prager
I found this out. The lp spring is the stronger spring (also longer), to allow more spring pressure to gas diaphram/valve. I converted a white rodgers vavle from natural gas to propane last week. And yes, the burner orifices need changed as well. Thanks