With the original filler neck filled, we began planning where to place the new filler neck. Those black lines indicate the left and rear edges of the tank under the floor. By using the fuel tank mounting strap bolts (arrows) as a guide, we determined the exact center of the fuel tank below. Roy decided to mount the fuel filler in the center of the floor. If you're going to store luggage in your trunk, this might not be the best place for it, but Roy generally drives a roadster so he packs light. We placed the filler as far back (closer to rear bumper) on the tank as possible to make it easier to access.