My 69 GTO convertible began leaking fuel today. It is coming from right rear top of tank, running down the frame rail just behind the right rear tire (above the tailpipe!). the books show a vapor return line and a vent hose, as well as the feed line coming from that area. It leaks intermittenly, after shut down, enough to cause a quick 10" puddle. Then stops. Other times I shut down, doesn't leak at all. Running better than ever, so doubt it is the feed line? Any idea how or what would cause the vent or vapor return hoses to leak? any help appreciated!