Hajek Sets Three Production Truck Land Speed Records At Bonneville - Dragzine.com
Jack, I tend to wonder about the front dam. Every modified "production" vehicle to run at high speeds, including the F250 link I posted above and most NASCAR style race cars, put one on. The idea is to force air around the sides rather than beneath for greater handling at high speeds. NASCAR is an endurance race more than anything so every mile you can get without stopping puts you ahead. Top speed just makes the miles go by quicker. If the airdam styling had hurt mileage they would not have used them.
Artie, when you raise timing you increase mileage quite a bit. When I was running canned tunes, just a .5 degree increase gave me 1 mpg in the city.
The gotts mod increase higher flow rate efficiency (above 2100ish) but has no noticeable effect below that.
Also, I installed a vacuum guage a while back (something you may want to look into) and the cruise control will consistenly lower the vacuum a few (inches/Hg) as compared to my foot. You can get them online for around $15 and you just hook a hose up past the throttle body. My truck actually had an extra lead in the vacuum system that I plugged directly into.
I'm thinking 4wd regearing will never pay for itself.
Find that guy who turned his couger into a bugatti clone. He is pretty dang good with fiberglass and making good body stylings.