It may not look like it, but the Ram full-size pickup you see here may be one of the more interesting new trucks on the road today.

You might view it as this decade's version of the Camaros, Mustangs, and Mopars that emerged in earlier days from back-corner "skunkworks" engineering groups at each Detroit automaker. How so, you ask?

This Ram isn't the run-of-the-mill SLT model that you'll see in the parking lots at every ranch supply store (or high-end shopping mall) in America's heartland.

That's HFE for High Fuel Efficiency.

The folks at Ram Trucks put a lot of work into thinking outside the box to create a full-size pickup that offers the fuel economy of a V-6 midsize sedan. 

And as we found, its EPA ratings of 24 mpg combined (21 mpg city, 29 mpg highway) actually underrate its fuel efficiency at highway speeds.

The recipe

The heart of this truck is what gives it the EcoDiesel badge: parent company Fiat Chrysler's 3.0-liter turbodiesel V-6 engine, which you can add to just about any Ram trim level.

(It's also available as an option on the Jeep Grand Cherokee luxury SUV, for that matter).

Designed by Italian engine maker VM Motori, now a division of FCA, the EcoDiesel V-6 is rated at 240 horsepower and 420 pound-feet of torque in this application.

For the record, it is fitted with a Selective Catalytic Reduction emission-aftertreatment system that injects a liquid urea solution into the exhaust at specified times to convert harmful nitrogen oxides into nitrogen and oxygen.

As well as its fuel tank, all EcoDiesel Ram trucks have a separate tank holding several gallons of diesel exhaust fluid, or DEF—which must be kept filled, or the truck won't run.

DON'T MISS: 2016 pickup truck fuel economy roundup

What makes the HFE version of the Ram 1500 unique is the way it came together as a product.

Fiat Chrysler's Ram truck team raided the proverbial parts bin for items to make this big truck even more fuel-efficient.

It's likely very similar to what their grandparents did back in the 1960s, looking for bolt-on parts to make their pony cars just that little bit faster.