I got it on ebay for $40 and free shipping. Its just a 1st get Lightning air dam. I would of rather done them in the bumper like yours, but didn't want to paint my bumper afterwards or have it rechromed due to the cost in California.
As for the MPG thread, I built a copy of the factory air dam for mine and ran it for a couple months. Some people claimed to get better mileage. However, in my case I didn't see any difference. The average speed on the freeway is 75 to 80 out here. The guy saying he got better mileage was more in the 55-65 range if I remember correctly. I think at the higher speeds and the shape of the truck, there isn't much that's going to make it better.
"Dumpy" 1983 F100
1986 Bronco II crawler
"Oh Blessed Lady of Acceleration... dont fail me now!" - Elwood Blues