Rtech Fabrications Ponderosa is a 20-foot-long Lucent Green giant

Remember when monster truck event commercials began with, “SUNDAY! SUNDAY! SUNDAY!”? The Rtech Fabrications Ponderosa needs a horn that blares just that exclamation. Idaho-based Rtech specializes in 1967-1972 Chevrolet and GMC trucks. For the Ponderosa, the custom restomod shop stepped out of its zone in paring a 1966 Chevy K30 Crew Cab conversion body with a 1972 C30 8,300-pound GVWR dually chassis on a 175-inch wheelbase. The result is a jolly Lucent GM Light Green giant that’s 8 feet tall, 20 feet long, and powered by a Ram-sourced Cummins diesel with 550 horsepower and 1,300 pound-feet of torque.

Rtech built the Crew Cab with 16-gauge sheetmetal, plenty of spot welding, and extra bracing in the roof to exceed factory rigidity. More strength hides beyond the factory front bumper, where a Warn 12,000-pound winch is mounted to a custom crossmember that also sprouts a Class V receiver hitch. Tubular steel rocker panels add further bracing, and easier entry with AMP Research Power Step XL running boards on custom mounts so they retract flush with the body. The body’s factory front doors serve as the rear doors, ensuring plenty of room for all occupants, and Chevy Stepside fenders on the 8-foot-long bed box make plenty of room for the rear rubber. Using hydraulic mounts between the body and frame injects more composure to the tall-boy ride. At the very front, a chromed grille from a 1966 Chevy pickup contrasts with the stock bumper, painted silver, and LED headlights. The bed’s been lined in ash wood, fits a fifth-wheel bed ball “just for fun,” and it sits over a 60-gallon tank to keep the party rolling.

The interior is a Chevy-themed custom living room. Custom vinyl and cloth 1966 GMC Sport Trim bucket seats wear the stock 1966 fabric pattern, above custom Daytona weave nylon carpet. And that center armrest is made from a GM hood. The stock instrument panel hides stock-looking Dakota Digital gauges, HVAC controls, and cruise control, a Bluetooth-compatible RetroSound Hermosa head unit running through a Kenwood amp and speakers, and custom windows and window switches, all powered by a Speedway Motors wiring harness. The navigation system doesn’t hide, hanging out front in the form of a Hull Manufacturing compass.

To the meat behind the potatoes: Rtech plucked a 5.9-liter, 12-valve Cummins diesel out of a 1996 Ram, then burnished the lump with a more powerful turbo and custom intercooler, Competition Cams camshaft and Mahle pistons, a ported and polished head, BD Diesel manifold, Dynamite Diesel Stage 3 injectors, a K&N intake, and Flowmaster four-inch exhaust. The valve covers have been powder coated to a custom green to contrast with the exterior green. Shifting duties get carried out by a New Venture Gear 4500 five-speed gearbox with a twin clutch, even though the shifter in the cab only counts up to four forward gears at the moment. Rtech Fabrications founder Randall Robertson told Autoblog he wanted to keep the old-style four-speed shift knob, but hasn’t had time to get the “5” inscribed on it yet.

Earth-mover power runs to a Dana 60 dually front axle and a Dana 70 rear, suspended by Bilstein’s 5160 remote-reservoir shocks and Skyjacker leaf springs. When it’s time to stop the mountain of verdure, high-performance pads clamp drilled and slotted front rotors, and 13-inch rear drums. At the corners, 37-inch Nitto Trail Grapplers wrap 20 x 8.25 American Force wheels. The period-correct, stick-thin steering wheel gets help moving all that rubber from an Offroad Design linkage and Saginaw 708 box, with Red Head Steering Gears to boost hydraulic power.

Roberstson said, “One of the main cornerstones of our business is to preserve the original look of a factory-made truck from that era.” That’s anything but the case here, and we won’t judge him for it. But Robertson, who’ll be glad to build another Ponderosa for anyone willing to chip in $150,000 plus extras, also says his firm provides “endless options for both drivetrain and interiors. Your truck, your choice.” As it should be.