Fiberglass hood mods... crazy?

The trouble with MythBusters is they tested newer trucks, if they would have tested several different trucks including older trucks, they would have come up with totally different results. Newer trucks, ones within the last 15 or so years were designed in wind tunnels so they do better with the gate up but the older trucks like pre 87 trucks were not wind tunnel designed and some do get better results with the tail gate down, especially ones from the 70's I've had a few mid 70's Fords and they do get better fuel economy with the gate down which would lead me to believe they have less resistance but my 92 and 93 Fords I have now gets better with the gate up. My father had several mid 70's Chevies and they also did better with the gate down.

Bottom line is it depends on the truck itself.