Figuring out how best to shave weight from the next-generation Chevrolet Silverado and GMC Sierra wasn't an easy task, with some General Motors engineers resorting to taking public tours of Ford's Dearborn truck assembly plant just to see how their rival handled its all-aluminum body.

Ultimately, GM opted for a hybrid solution of sorts - some aluminum, backed up by varying grades of steel, to slim down its 2019 full-size pickups. But the obsession with Ford didn't end with the plant tours.

Speaking to Reuters, Tim Herrick, executive chief engineer for GM's truck programs, said his spies noticed, "[Ford] had a real hard time getting those doors to fit." With stopwatches in hand, they watched and timed the operation as the F-150s moved down the line.

Focusing on the doors, Herrick's team bought and disassembled F-150 doors sold as parts. It was then they realized GM could get away with using thinner, high-strength steel plus aluminum to shed pounds (up to 450 lbs per vehicle), without having to make the entire body from the lightweight commodity. Seven grades of steel make up the cab, while aluminum is the material of choice for the doors, hood, and tailgate.

Tariffs and rising aluminum prices are currently hurting Ford's profits, but GM's not exactly outside the boat. There's also new tariffs on imported steel, and the rise in commodity prices have taken a chunk out of GM's earnings, too. Still, the team's glad they didn't go all-aluminum.

Herrick claims the company battled with the decision at all levels ("it was a really hotly contested item for us"), but feels the decision to mix metals will ultimately help the company reap a larger windfall per truck.

"We think we have thousands of dollars advantage (over Ford) just in the aluminum costs. It's big," he said, adding that the extra profit will help fund other programs while keeping shareholders happy.

The reduced weight of the slightly larger crop of 2019 pickups meant the opportunity to do the unthinkable: add a four-cylinder offering to the engine mix. Backed by a host of efficiency-minded tech, GM's turbocharged 2.7-liter "Tripower" inline-four generates 310 horsepower and 348 lb-ft of torque, and could give the General an edge in the full-size fuel economy fight. Currently, no EPA ratings exist for this mill.

We'll have a first-drive of the 2019 Silverado for readers next week.

a version of this report first appeared on