Just a random though as I was staring at a newer truck today. In the quest for mpg, newer trucks have bumpers and air dams that extend much closer to the ground. Has anyone ever experimented with something like this? It would be interesting to see the effects it would have on our trucks.

I don't know about air dams... redesign to lower bumpers was because of Federal Crash Regulations.

Here is a good reading about Aerodynamics.

I noticed about 1 MPG gain to MoparMom's 1996 Dodge with and without the factory air dam on her truck. Even though the air dam is only about 3 inches it does actually help the MPG's by reducing the wind drag under the vehicle. If I was to drop the truck a few more inches I could gain even more.

That's a good link. There is a good amount of info in that thread. It's funny if you look at the hybrid Chevy trucks how low the air dam is compared to the rest of the vehicle. 1 mpg is quite a difference considering what a simple piece it is. On a somewhat related note, I saw a 2nd gen with rear fender skirts. Don't know if they were a custom job or what, but they carried the lower body line through them and everything so it had some thought put into them. Just though it was a very interesting modification.

If there was a lower air dam for a late third gen I'd love to put it on my new truck. The stocker has a rip on one spot and is sagging in a few others.