I'm looking to replace an old oil furnace on a rural property with a
propane furnace. I intend to do it myself. Since the property is
just a hunting cottage I am not looking to spend a lot. I am actually
looking for a used furnace if I can get one. My question is whether
gas furnaces are specifically made for natural gas or propane, or are
they all the same and just need a different orfice(s) intalled to
match the type of gas used? Anyone know?

Thanks

Jimw