When Brent Casteel found a 1970 Chevrolet Suburban for sale in Spokane, Washington, it checked the right boxes: factory Medium Green paint — a color only available on 1970 models — solid bones and an original 350 small-block backed by a TH350 automatic. Brent, who lives in North Carolina, didn’t hesitate.
He just didn’t ship it home. Instead, he and his son flew to Washington with a suitcase full of tools and a plan to drive the Suburban cross-country.
“Before heading out to Spokane, I called a local parts store and had them order everything I could think of that might fail on the drive home — distributor, water pump, alternator,” Brent said. “We didn’t use a single spare. The engine and transmission ran perfectly the whole way.”
The Suburban was equipped with a factory auxiliary fuel tank, but the previous owner had never used it. With the truck averaging about 10 mpg, having the extra capacity would make a big difference on a cross-country drive. After filling the secondary tank, Brent flipped the mechanical selector switch and waited.
Nothing happened. No sputtering. No drama. Just more fuel. That would never happen for us.
With 46 gallons of total capacity — 21 in the main tank and 25 in the auxiliary — the Suburban spent more time covering miles and less time idling at gas pumps on the way back to North Carolina.
Once home, Brent transformed the Suburban into a true long-haul machine. A 2003 Chevrolet Tahoe became the drivetrain donor vehicle, contributing its 5.3-liter V8 and 4L60E overdrive transmission. Using Dirty Dingo engine and transmission mounts, Brent shifted the powertrain forward 2.5 inches for optimal fitment while retaining the factory accessory drive and air conditioning compressor location. A PSI wiring harness and ECU simplified integration.
Fuel delivery required custom plumbing. The primary tank now uses an in-tank pump, while the auxiliary tank uses an external pump. During the conversion, Brent inspected the secondary tank and found it remarkably clean inside. With 3.73 gears and a Yukon Gear posi differential out back, the Suburban now returns about 19 mpg on the highway — nearly doubling its original fuel efficiency. Combined with the 46-gallon capacity, it delivers genuine all-day cruising range.
Nicknamed “Gus the Green Bus,” the Suburban isn’t just about power and range. Brent upgraded the braking and suspension systems with components from CPP, including four-wheel disc brakes, a rear air-suspension setup for load leveling and new front springs for better ride quality. The Tahoe donor also provided modern front, second and third-row seating. Custom mounts secure the third row, while the second-row captain’s chairs were swapped side to side so the armrests face inward. Dakota Digital VHX gauges replace the factory cluster with modern meters.
Originally equipped with factory rear air conditioning, the Suburban channels cooled air through ceiling vents for second- and third-row passengers. Brent added a Vintage Air system for the front occupants. Brent purchased the Suburban in 2022 and, since completion, he and Sharon have logged more than 53,000 miles in the 3-door ‘Burban. Gus has been driven in all but roughly a dozen states, with plans to cover the lower 48 — and possibly Alaska — in the coming years.
This isn’t a restored Suburban that lives under a cover. It’s a 1970 Chevrolet built to roam — a classic SUV being used exactly as intended.