We have done numerous tank relocations during the years and favor the early Blazer tank over the Mustang as it has a left side filler neck and plumbing is easier. You can use exhaust tubing (won't rust) to locate the filler neck anywhere. My personal favorite is the motorcycle "Pop Up" cap pictured below. It fits flush with fender surface so you turn it 1/4 turn and it pops up and then screws out just like ones on modern cars. No doors to mess with and if painted body color it's nearly invisible.

[img]https://i.postimg.cc/MXgwrtMt/003.jpg[/img]

[img]https://i.postimg.cc/75VpDN6F/004.jpg[/img]

[img]https://i.postimg.cc/TpckW36m/008.jpg[/img]


Evan