The Cummins would be nice in my 87 slant 6 regular cab short-bed for mileage, but probably easier to swap in some variation of a V8 - 273/318/340/360/later Hemi
The Mercedes 5 Cylinder Turbo Diesel would be a decent option too. You can find them in everything from 80’s to Present cars, vans, etc (even the Dodge Sprinter vans).
I put one in my ‘92 Dakota with an AWD Conversion, all in all the whole swap cost me $400 and now the truck averages 33mpg and has enough power to burn all 4 tires through the first 2 gears, and enough torque to break factory Dakota parts (like the Spool Motor Mounts for example)
