Another update...
Friday I made my own lower bed seal (to the cab) to finish off the 3 seal install that the newer rams have. Was surprised by how much farther I can coast before loosing too much speed. It made a noticeable difference.
It is all detailed in this thread... would need to go back to the previous friday in that thread for pics of what I did.
https://www.cumminsforum.com/threads...#post-29492601
After the install I short filled the tank so I have good data for 4 days of commute driving to compare against. Was surprised to get a 21.1 mpg out of the 125 miles on that tank. That is high for my truck given that 90% of the miles were all in town... (nothing is flat here so I get to coast a lot).
Looking at doing some ducted cooling changes in an effort to relieve the high pressure at the front of the truck. If that is successful then I also want to see about leveraging the heat extracted to feed a rear diffuser I plan to build a the back of the truck. The goal there being to help reduce the vacuum pull at the back of the truck. I think there is some decent gains to be had there if I can get the diffuser fed with air correctly. That is a long term project.
I did manage 3 tanks of 23.5-23.6 mpg's in a row, followed by a 22.x tank on a road trip, AC blasting on the return & both e-fans on. Not bad for a 7k # 4x4 truck (I think anyways). Walking up to my truck, you'd have to have an eye for aero mods to notice anything is different from the factory.