What is the diference between the 350 and the 500 models, since the size is the same and most of the parts are interchangeable?
What do we need to change to transform a 350 in a 500?
Main difference is the nozzle (350 instead of a 500) and the needle.
In addition, you can use a 350 mantle , but in my 350 lamps, a 500HK mantle does work well.
However, sometimes you catch 500 HK mantles which are quite big, then the use of the next smaller size may be necessary.
Brightness of 350 to 500 is not much lower, fuel consumption is less and the noise as well.
Note that the heating power will be slightly reduced also (if you intend to use the Petromax for heating also)
Just try it.