The thing with two engines: The Grico Twin-Motor Ford Truck

In 1939, a Motor City company named Grico solved the power problem in trucks in a novel way: with a pair of V8 engines stuffed in a Ford cabover tractor. Here’s the story.   



Today’s over-the-road trucks have something we take for granted, a property the big rigs of the late ’30s were sorely lacking: cheap, powerful, reliable engines. (You know the old joke: Choose any two.) The best Ford had to offer was the 221 CID V8 with 85 hp, or the 239 CID Mercury/truck V8 with 95 hp. There were more powerful powerplants available, sure, including the brand-new GMC 6-71 diesel introduced in 1938, but the GMC was not yet proven and it wasn’t cheap, either.

Into the breach stepped the Grico Two Axle Drive Co. with its clever solution, the Grico Twin-Motor Ford Truck. Grico was a spinoff division of the Gear Grinding Machine Company of Detroit—a company that happens to be one of the greatest Motor City stories never told.

Gear Grinding Machine’s leading technical mind was Alfred Rzeppa (pronounced Cheppa, approximately), the inventor of the Rzeppa constant-velocity universal joint. A key component in all modern front-wheel-drive cars, the Rzeppa joint was just one of the Gear Grinding Machine Company’s many critical contributions to the auto industry. But today, few have heard of the company, even in the industry.

As the name indicates, the Grico subsidiary’s chief product was tandem axle setups for heavy-duty trucks, and the Twin-Motor Truck might be considered a logical extension of that approach. The Ford COE tractor’s original V8 engine, drivetrain, and rear axle were retained. A second V8 engine, transmission, and driveline were installed behind the cab, under a sheet metal housing, driving the second axle in the tandem.


The two powertrains were configured so that either one could be operated individually to propel the truck, or they could be run in tandem controlled by a single throttle, clutch pedal, and shift lever. How many Twin-Motor Trucks were produced is not known. However, while it was quite possibly the first, Grico was not the only builder of dual-engine Ford trucks in this period. Manufacturers included Spangler, E&L, Merry-Neville, Thorco, and others. But the trend didn’t last. Modern, high-output diesels were already on the way, and one engine would prove to be enough.


12 thoughts on “The thing with two engines: The Grico Twin-Motor Ford Truck

  1. Thanks for a great article, being an old trucker, I can sure sympathize with the drivers of yore. The first heavy duty truck I drove was a 1963 IH R-190 with a 450 Red Diamond gas engine. I always thought there was something wrong with it, because on many occasions, I couldn’t even get it in the last gear. I’ve actually seen the truck mentioned here, at a truck show, and it drew quite a crowd. I’ve also driven trucks with 238 Detroit diesels, and quite frankly, they weren’t much better than the gas jobs. This article reminds me of another engine in the ’60s, the GMC ” Thunder” V-12 gas motor, basically, 2 V-6’s sharing a common block. Rated at 250 horsepower, they were no match for the Cummins and Cat motors and were dropped after 1965.

    • Most of the gas engines used in heavy trucks had a governor carburetor that used vacuum to control the throttle shafts. Basically there is was not a direct link between the throttle shaft and throttle pedal or other throttle control. Other wise the load on the engine would cause it to blow up

  2. The closest thing to a twin engine down this way (Australia) was using a horizontal bus motor under the floor of the trailer to power the trailer. This was seen a few times in the 1960’s when the Allison transmission made it easy.

      • They would just use the truck motor on the flat ground but when it came time to climb into the mountains they would fire up the extra motor with electric controls.

        • Hi Michael, That’s incredible, sometimes we talk about those being “the good ol’ days”, but I remember my grandparents saying they weren’t so good. Bet it was a slow ride if that second engine didn’t catch right away.

    • That is the E&L tandem which came out a few years later. I’ve been told there were many of them running around Willow Run during the war. There are still one or two in existence.

  3. Best of Old Cars vol 5, No.25, out of krause publications ran an article that included dual and triple engined experimental trucks built by the Toronto Star paper in their own shop in the 40’s to haul large newsprint loads for country routes. A few black and white pictures and text discribbing the builds..

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