Answers for buckyball:
Air dam material is 3/4 x 24 inch wide conveyor belt.
The slot is for my tranny cooler. Yes, a ZF6 requires a tranny cooler.
Ground clearance started at 1 inch but is now 1.5-2 inches.
The bumper is an OEM Excursion bumper with Rhino Lining sprayed on. I recommend that.
Fairing cover material is rubber stair runner, back side out. I needed something that would bend in two axes and it happened to be laying around. It is fastened to the frame with cove base adhesive and drywall screws and fender washers. It has lasted better than I thought it would. It even shrank a little giving me a fair smooth surface.
Two transverse ribs. 3/4 inch plywood.
More pics
http://www.fokisd.org/gallery2/main.php?g2_itemId=508
No grille block to date but that is on the "to-do" list. I intend to go whole hog right away and work toward having operable dampers to back off the grille block as the engine/AC get hot.
The fairing is worth 3 MPG over an open bed. The air dam came too late in the year for a fair test. I'm working on a more rounded air dam to push the air side rather that the bluff thing I currently have.
Side skirts and fender skirts are also in the works. I intend to put Mooneyes on the wheels to clean them up some.
Since you are a 4x2 you can consider slamming the truck. Mine has a 3 inch slam up front (plus lowewred another inch by going to 225 tires) and a 6 inch slam in the back. That was good for another 1-2 MPG.
I also went to 3.08 gears. This was a powerful tool, gaining me 2.5 MPG. If you do this you may want to contact Brian's Truck Shop in Arkansas. He builds super performance automatics that can live with a numerically low gear ratio. That ratio will flat kill an OEM automatic.
You gotta figure out some way to defeat the EGR system (if you are off warranty). That robs the 6.0 of efficiency. It is also the cause of many reliability problems for the 6.0.