Welcome back!
You are probably on the right track starting with aero. Make sure you do aero mods over and under the truck. Keep the cruising speed down, if possible.
Find the highest/tallest geared rear end that you can.
Get a manual/OD transmission if it doesn't already have one.
How far are you willing to go? Get some high CR pistons. Get an economy cam & time it for efficiency.
While it's apart, maybe omit a couple of pistons & seal off the oil holes in the crank. I'm not saying it will run well, but I delegate you to be the first to try it!
