The Cummins Repower 2.8L Turbo is Right at Home in This 1977 Gremlin
Crate Is Enough
What’s a Gremlin? There are probably more than a few readers out there wondering about this unique ’70s subcompact. American Motors Corporation introduced its low-priced economy car in 1970, at a time when gas prices began to rise and fuel mileage became a priority for car buyers. The smaller AMC was in competition with segment leaders such as Chevrolet (Vega) and Ford (Pinto), but Gremlin was on the fast track, beating the bigger brands to market by more than five months.
Its controversial style was a cost-cutting measure that cobbled a shortened AMC Hornet platform and bodywork together with a pronounced, almost vertical “Kammback” tail. Faster than the four-cylinder Chevy and Ford and the anemic 40hp Volkswagen engine, the Gremlin’s 145hp, 232ci I-6 made it the leader of the pack. Over the years, engine size and displacement increased, with a stout 304ci V-8 eventually making its way onto the Gremlin’s option list. The real performance news, however, happened in 1972, when Mike Randall of Randall AMC in Mesa, Arizona, got the OK for a high-performance Gremlin project. Providing “unofficial” approval, AMC shipped 30 of its 401ci V-8s—the biggest and strongest engine in the lineup—and the Randall 401-XR Gremlin was born.
Like the high-performance, dealer-modified Yenko Camaros, Randall’s cars were special in every way. He promised his pure stock $2,995 Gremlin could run 13.9-second e.t.’s in the quarter-mile and, with a few of his choice performance options, times could drop to the low 12s. These are respectable times today and (for the money) were amazing back in the early ’70s. AMC sold more than 670,000 Gremlins during its eight-year run, but there are a growing number of collectors who now realize good ones are becoming hard to find.
Larry St. Amand, from North Fort Myers, Florida, owns Florida Torque Converter in Cape Coral. He and his wife, Christina, are avid Gremlin enthusiasts, with Chris remembering the ’76 she had in high school. They decided it would be fun to have another, especially one with a unique powerplant under the hood. Since there were only 21 Randall 401-XRs actually built, those were out of the question. Instead, Larry went an entirely different route, deciding to use his mechanical talents to create his own one-of-a-kind Gremlin special.
A diesel event is the catalyst that got this unusual conversion started. Larry and Christina not only love the car, but they’re also big fans of the Scheid Diesel Extravaganza, held every year in Terre Haute, Indiana. Six weeks before the August 2018 event, Larry decided an oil-burning Gremlin would be the perfect ride for getting there. He had already found a freshly painted ’77 AMC Gremlin X Levi’s Edition, located in Arizona, rust-free and ready for personalizing. Since he works with diesels on a regular basis at his shop, Larry knew all about the Cummins Repower Program and was intrigued by the R2.8L crate-engine package. Even though the 161hp turbocharged I-4 delivers 310 lb-ft of torque and is oriented more toward Jeeps, Larry feels it is the perfect choice to energize the little Gremlin.
Starting with a comprehensive plan, Larry’s goal was to package everything carefully in order to make it look like a factory installation. Having created dozens of cool customs in the past, it was easy for Larry to set the R2.8L in place, make the engine mounts, and adapt an intercooler from a Ram Sprinter van. He ordered a brand-new three-row aluminum Gremlin radiator, but it turned out the brackets were assembled backward. Capitalizing on the mistake, he used the gap between the intercooler and radiator to route all the hoses. On the passenger side of the engine, stacked on top of each other, are the alternator and power steering pump. Larry squeezed in the A/C compressor at the bottom for a tight fit. The belt had to be routed creatively, but everything functions perfectly. Using an Axis Industries Cummins-to-Jeep conversion kit, the stock Gremlin bellhousing, and a LuK Jeep clutch with hydraulic linkage, Larry was able to mate the engine to a Ford-type Tremec TKO 500 five-speed manual transmission supplied by Silver Sport Transmissions. Wrapping up the powertrain, a custom driveshaft feeds the stock 2.87 rear end.
Imaginative touches are everywhere on the car, like the air cleaner hidden in the passenger-side front fender with baffles to keep water out. Since space is at a premium in a Gremlin’s engine bay, the driver-side wheelwell holds the remote oil filter and fuel filter. Larry found room for a pair of AGM batteries, laying them flat in the muffler location behind the driver seat. The 2.5-inch exhaust is fully wrapped and fitted with a single turbo muffler and a custom exhaust tip. Even the stock cruise control is adapted to the Cummins electronic gas pedal.
Once the engine conversion was complete, Larry concentrated on handling—retaining the stock suspension but adding 16-inch steel wheels and wider, 55-series radial tires along with a modern steering box and new shocks. Although the diesel weighs a bit more than the original Gremlin six-cylinder engine, Larry says the gain is minimal and handling actually improved with the wider rubber. Moving inside, the original seats are replaced with a pair of buckets from an Alfa Romeo found in a salvage yard. The three instruments in the center console include the multi-gauge from Cummins, a boost gauge, and a clock. Four warning lights monitor underhood activity and a modern OBD-II port makes troubleshooting easy. It also simplifies downloading the latest PP1 ECM calibration for the engine.
Amazingly, the conversion was completed sooner than the six-week deadline and Larry and Christina enjoyed the 2,500-mile round trip to Indiana, entering the car in the Scheid Diesel Extravaganza show ’n’ shine. The diesel Gremlin was a big hit with spectators at the event as well as at every fuel station along the way! It averaged 38 mpg, and the trip was trouble-free. Future plans include a few minor upgrades, including disc brakes on the rear and an upgraded stereo system, but the Cummins-powered Gremlin is complete and destined to provide family fun for years to come.
Fast FactsYear/Make/Model: ’77 AMC Gremlin X Levi’s Edition
Owner: Larry and Christina St. Amand
Hometown: North Fort Myers, Florida
Odometer: 68,191 miles
Engine: 2.8L Cummins I-4 r
Fuel: Cummins fuel separator, modified stock tank
Air: Custom canister-style filter
Exhaust: 2.5-inch, turbo muffler, custom exhaust tip
Transmission: Tremec TKO 500 five-speed manual
Horsepower: 161 hp
Torque: 310 lb-ft
Tires: 215/55R16 Solar
Wheels: 16-inch steel
Interior: Alfa Romeo seats, custom gauge panel, cruise control, air-conditioning
Fun Fact: Larry says, “I told my wife the Gremlin needed a new carburetor and an exhaust leak fixed, and I put it on the lift. Six weeks later, I had shoehorned a new diesel engine in it. Problem solved!”