Fully welded into place, the replaced section of floor is as solid as the original, and without nonoriginal overlapping seams it would be difficult to detect that it has been changed. The final step is a healthy layer of seam sealer applied at the firewall joint and along the rocker panel edge. The factory used a heavy application here. We will build-out the tunnel once the engine and transmission are mocked-up into position. The side of the tunnel, originally cut out by the factory for the four-speed hump, was nicely filled-in by the new floorpan section.