After making the tunnel and bottom of the tank, I welded in the stand pipes and fittings for the oil section. Then, with the oil tank section welded to the fuel tank bottom, I welded in the neck for the oil tank to exit through the top of the fuel tank. I hammered and shaped the side and top panels, then built them up around the oil tank to create a fuel section. You can see the oil filler neck coming through behind the fuel filler neck. The scalloped cut aways in the sides are polished stainless.