340 Dart - Fuel Filter location

I would like to know where is the best location to install a fuel filter on my 1970 Dart Swinger 340? My neighbour who has a 69 - 340 tells me that it should be installed just before the mechanical fuel pump between pump and fuel tank. From most pictures that I have seen, it shows a filter located just before the carb after fuel pump. What is the proper location or should I install a filter in both locations?