Big Green vs. Ike Gauntlet! How Does 1985 Chevy K10 Tow 6,000 lbs Up and Down a Mountain?

1985 chevy k10 truck towing extreme review
Big Green K10 on the Ike Gauntlet extreme towing test

How much┬áhave pickup trucks improved over the last 32 years? Can our 1985 Chevy K10 “Big Green” project truck handle a sizable trailer down and up the Ike Gauntlet towing test – world’s toughest truck test? Will the brake controller work? Will the engine blow up on the way up the 7% grade to over 11,000 feet of elevation? These are just some of the questions running through our minds on the way up to this Rocky Mountain test.

Big Green is a long-bed K10 4×4 pickup truck with a four-inch lift and stock drivetrain. Under the hood is a 305 cu-in carbureted V8 that (when new) was rated around 165 horsepower and 240 lb-ft of torque. That was 32 years ago, and the maximum altitude of the Ike Gauntlet is 11,158 feet above sea level. There is approximately 32% less air density at this altitude, which means the engine is starving for oxygen. This truck has a 4-speed manual transmission (3-speed with a “granny” low first gear). It’s rolling on 10-bolt axles front and rear and turning 35-inch tires. Rear axle ratio is 3.73, which is a good one for towing.

We are towing a CM Trailers 20-foot CargoMate, which is loaded to a combined weight of 6,000 lbs. This does not sound like much by today’s standards, but this K10 was rated at a maximum towing capacity of 6,500 lbs. This truck is basically maxed out on load.

Ike Gauntlet is an 8-mile stretch of I-70 from the Eisenhower/Johnson memorial tunnels down to the Silverthorne/Dillon area. At 7% grade, this is the steepest and highest elevation interstate highway in the country.

Safety is the number one priority at TFLtruck, so we had to make sure that the old brake controller on Big Green was properly activating the trailer brakes. This took longer than we expected, as the old wiring and the 6-pin connector on the K10 gave us issues. We finally resolved the problems, and off we went!

How did the truck handle the downhill? Did it overheat? How fast was it? Check the video for all of the excitement and details!