[aardvarcus]

All,
First of all, I appreciate everyone’s willingness to share their knowledge on this site. I thought I would share a project I have and hope to get some constructive feedback. Having read most of the truck related posts on this site, I made a background section to fill in most of the blanks many people leave out. Those wishing to skip to the heart of the matter can go down to the real discussion section below.

----Background----
First off, my daily driver on my 100+ mile round trip daily commute is a Toyota Celica (36-38 MPG). I also have worked construction in the past and am presently building my own super insulated house. My daily driver from home to the construction site is a 1991 Chevy K2500 Light Duty (6 lug ¾ Ton). This truck “works” but is falling apart and I am constantly fixing things on it (Transmission Issues, 4WD issues, Etcetera). I needed a heavier duty truck to do some of the more demanding construction related tasks as well as a truck I trust to drive more than 30 minutes from the house. To this end I purchased a 2001 Chevy 2500HD 4x4 extended cab with the 8.1L Gas Burner and the Allison Automatic Transmission. Its present use is hauling heavy loads I don’t trust the other truck with, hauling lighter loads that go a distance from the house I don’t trust the other truck with, and as the only four door vehicle we have hauling 3-5 people when necessary. I know the last two uses are a waste of the trucks capacity and already have plans to address that.
To answer some of the initial feedback I already know I will get:
You should have gotten a Diesel: Probably but couldn’t find a decent one in the budget, and yes I am going to pay for it in the long run. May do a Diesel swap if the engine goes kaput.
You should have gotten a Manual: I desperately wanted one and searched for three months for one that wasn’t way overpriced or beat to death and I was going to keep searching, but I could not pass up the deal I got on this truck. May do a manual swap if the transmission goes kaput.
You should buy a four door car so you don’t have to drive that dumb truck around when you have people you need to take somewhere: I am planning on getting my wife a smaller four door car after the house is done for this very reason.
You should have gotten a half ton/midsize: After the house is built, I am planning on selling the anemic K2500 and buying a half ton or midsize for most of my daily use, but I still need the heavy duty truck for harder hauling (3000lbs+) and towing (10000lbs+) and for “abusive” use (pulling logs through woods, etcetera).

----Real Discussion---
So basically I am going to have this truck for quite a while (unlike my other vehicles) so I would like to begin to squeeze the best economy I can out of this behemoth, though I hope in the future to be using it less and less. I have been averaging 11 mpg with a mix of construction use and town and back hardware store trips. On mainly highway driving with light loads I have been getting closer to 14 mpg. Honestly it is getting very similar to my k2500 which only has the 5.7 in it.
My goal is to get those numbers to 14-15 mixed use and 18-19 highway long term. I am planning to do this though a variety of modifications done slowly over time; however I can’t do anything to make it less of a 1 Ton truck. After tuning the engine, I have plans to make some aerodynamic changes to the body, however at the downside of adding weight. The truck is already very heavy and I feel that the weight aspect is already a lost cause. Anything I add to the truck needs to be able to withstand the rigors of its use, and while I have no intention of going crazy and welding ¼” plate to it, any body modifications would probably involve thin sheet metal over a tube frame, which will make it heavier. Here is what is in the works:

Completed Mods-
Changing all fluids to synthetic. (Engine, Transmission, Transfer Case, Differentials)
255/85/16 All Terrain Tires (Not the most fuel efficient, but for the ground clearance and traction I need a better fuel economy choice than 285/75/16 Re addressing below)

Currently underway Mods-
Replacing Spark Plugs and Wires
Tuning Engine/Transmission to increase Efficiency

Planned Near Term Mods-
Hard Folding Bed Cover
Additional Street Tires for better on-road economy (235/80/17 Michelin Street Tires- Green X, mounted on extra set of rims)
Transition Filler Pieces (Cab to Bed, Hood to Windshield, etcetera- Probably Foam)
New Shocks (Not so much for efficiency)

Mid Term Mods-
Belly Pan (Improve airflow under truck- Must Have Decent Metal Frame, will do either thin sheet metal or coroplast over metal frame for actual Pan)
Step Bars Incorporated into Belly Pan Frame (I pulled off the non-aerodynamic step bars, and my wife didn't exactly appreciate it.)
Aerodynamic Tire Transitions
Rear Suspension Drop (Due to body rake can lower back a full 3” with only ½” loss in ground clearance)

Long Term Mods Under Consideration-
“Fastback” Cab to Bed Wing Transition (Like the first 1/3 of a full sloping aero shell, to complement Bed cover similar to wing that Texas Tech used)
New Heavy Duty Front Bumper/ Clip (Incorporate entire front clip into new bumper, aerodynamically shaped, shuttered front grill that partially closes at high speeds) (Will add significant weight)
New Heavy Duty Rear Bumper (Smooth transition from belly pan out, will also add significant weight)
Electric Fans
Air Bag Raising/Lowering System (Probably too complicated to do correctly with no loss in capacity)

You all are the experts, so feel free to critique my planned mods, offer insight, suggest mods, etcetera.