Squeeks,
This is a good mod if you need the extra capacity. I pulled the internal stock filler hose out upon doing this mod. Also took a hole saw (in drill press) and drilled out the necked down part in the filler neck. In addition I plumbed in a 1/2" ID vent line by removing the roll over valve, cutting only just the very top off and JB welding in a brass low profile elbow and removing the internal rollover bits inside. Ran 1/2" I.D. diesel proof tube forward then to the filler elbow where I JB welded nuther brass elbow to vent out the air when filling the tank. Good idea to R&R all at once. I put my tank in last fall had it spit fuel back at me a number of times (and slow to fill) then did the vent mod just last week...have only fueled once since but seems to work real well. Took pix of the JB welded stuff and will post a bit later as I'm workin away from home right now. With this tank, stock front and drybox combo fuel cell now at 405 litres (107 US gallons).
jrc