[aerohead]

There was some discussion of bigger truck fuel economy over at maxmpg.A couple of years back,Popular Science did a mpg comparison between a GM 3/4-ton diesel pickup and a Ford Taurus.I take issue with their methodology as they seemed to mix apples and oranges,however they did site some recommendations for fuel economy by Rich Taylor,Chief of GMC truck division.

As per Taylor's recommendations,the magazine's crew blocked some of the grille,fabricated a partial bellypan for the sides of the under-chassis,leaving the center exposed (presumably for cooling insurance),and installed a tonneau cover over the bed.

An internal memo pegged the gasoline truck at, I believe,17-mpg,the modified diesel,at 55-mph,returned about 26-mpg.

Members have discussed a gradual blocking of the grille and then monitoring temps.Good idea! As with GM,the Ford cooling system may be designed to deal with Death Valley,at the peak of summer,with all accessories on,at idle.I suspect,short of those conditions,one could safely block some of that grille with no ill effect.

If the chin spoiler is not as low as the lowest suspension member,an addition to the spoiler would block some air from the underside,giving some of the benefit of a bellypan.

The truck is heavy,but there's little you can economically do about that.

Around town,aero mods won't show up at the diesel pump. If you do a significant portion of highway travel,then the back of the truck is where your fuel is going.Anything you can do to clean up the wake will pay dividends.