[aerohead]

Many good comments,suggestions.Since I'm late to the party I apologize,however had a few things to toss into the pot.The pickup allows many avenues,and as Smoky and others have mentioned,the Kammback isn't necessarily the only way to go.A topper,level with the roofline of the cab will offer savings.A tonneau will help.A half-tonneau oddly enough,will offer greater savings than a full tonneau.A cab-extender (sail panel extender) which converges on the sides at about 7-degrees,and falls in a curve down from the top at about a 12-degree angle,and is 18-inches,to,24-inches in length will show up at the pump.The cab extender and half-tonneau together,will give results close to that of the aero-shell,with greater utility,however perhaps less security and weather protection.Rich Taylor,GMC Truck Division Guru,says grille-block,partial bellypan,and tonneau is good.The 194-mph GMC Sonoma used the Moon wheel covers,California styling package,stretched the cab,lowered the truck,and did the patented GM half-tonneau for its land speed record (read higher mpg) at Bonneville.The Sonoma achieved Cd 0.31 ( about that of the day's Corvette).Whatever you do,make it robust enough that it doesn't blow off the truck,endangering other motorists.Naughahyde stretched over a skeleton of electrical metal tubing,with tack-strips screwed to the tubing,provided a simple,lightweight,and durable cover for one of my neighbors for years on his Chevy C-10.Fields wide open!