Beatdown Z, your gonna need a wideband to see what's going on.

 

Truck sound great.

Are you sure your tach is accurate? Doesnt seem to be in the 1st vid in this thread.

peace
Hog

 

As far as I can tell it's accurate. It's a Autometer Monster tach hooked up to the tach output of the MSD 6a, it's been this way for years and reads accurately while cruising for the gear ratio & tire size. (ie: 75mph @ 2300rpm) It also matches the tach on my digital timing light

 

If you're still worried about aerodynamics, partially blocking off the grill (like an srt ram) and adding a roll-up soft tonneau (gained just over 1 consistent mpg on my '05) could help. If all else fails, try a late 70's (adjustable part throttle) q-jet 14 mpg isn't bad for your setup though