Hey Greg - I love the ideas and thought that is going into this car. On the tank fill, Petersen makes a tank with an angled spout/cap which would give you some clearance from the top of the fender if you moved the tank inward just a bit. Doesn't look like it would clear from where it sits now.
On that note, will the tank even clear the fenders? Looks like it sits a bit farther out from the pics.
