The most powerful American production car engines ever made

Slide of Internal combustion engines are far more complex than electric motors, and it’s correspondingly more difficult to make them produce a lot of power. As the 2011 horsepower Lotus Evija demonstrates, the most powerful cars of the near future will be EVs, but remarkable outputs have nevertheless been achieved with engines fuelled by petrol or diesel. Here we’re looking at 20 of the strongest examples created in the US, all of them available in cars or non-commercial trucks sold to the public for road use (so no 11,000 horsepower Top Fuel dragsters, for example). They’re listed in ascending order of their quoted outputs, with the caveat that there was a change from gross to net horsepower in 1972, which muddies the waters considerably. Only the most powerful unit from any family is included. This means that what you’ll be reading isn’t a top 20 in the usual sense, since many engines have been ignored because they are outpowered by close relatives, but it adds variety, and we all like variety. Slide of Chrysler FirePower: 390 horsepower (gross) The FirePower was the first of three generations of Chrysler V8 engine collectively known as Hemi. Introduced in the 1951 model year, it was the only engine fitted to the first four models in the 300 letter series, each of which was produced for just a single year. It was discontinued after the 300D of 1958, in which it produced 380 horsepower from 6.4 litres if fitted with twin four-barrel carburettors. Optional fuel injection raised the output to 390 horsepower, the highest achieved in any FirePower. It’s important to note that this was a gross figure, measured when the engine was not burdened by power-sapping ancillaries necessary for it to function in a car. The net figure, as used from 1972 onwards, would have been lower, but still comfortably over 300 horsepower. Slide of Chrysler RB: 400 horsepower (gross) The RB was a big-block V8 offered in capacities of up to 7.2 litres, but the most powerful version fitted to a road car measured 6.8 litres. This was used in the 300F of 1960, in which it normally produced 375 horsepower gross. As an extra-cost option, customers could order a 400 horsepower version, which was mated to a four-speed manual gearbox rather than the usual three-speed automatic. The highest gross figure for a 7.2 was 390 horsepower. The Max Wedge variant was rated at 420, but this was intended only for use in drag racing. Slide of Ford MEL: 400 horsepower (gross) The MEL (which stood for Mercury-Edsel-Lincoln) was Ford’s rival to the contemporary Chrysler RB. In 7.0-litre form it was easily capable of producing 360 horsepower, which was the standard output of the Mercury Park Lane. In 1958, however, Mercury offered an uprated version with three two-barrel carburettors. Known as the Super Marauder, it produced 400 horsepower, and was an option on every model Mercury sold in that year. Slide of Oldsmobile Rocket: 400 horsepower (gross) In 1970, the final model year of the first-generation front-wheel drive Toronado, Oldsmobile created the optional W-34 package to boost the output of its second-generation V8, which by that time had reached its maximum capacity of 7.5 litres. As standard, the V8 was rated at 375 horsepower, which you might have thought would be about enough. The uprated camshaft and dual exhaust system included in the package raised this to 400, and for good measure Oldsmobile added “special transmission calibration for quicker acceleration”. Slide of Cummins B Series: 420 horsepower The first and only six-cylinder diesel on this list is a 6.7-litre member of the long-running B Series family, supplied by Cummins to Stellantis for use in its Ram heavy duty trucks. The Standard Output version produces 370 horsepower and is available in the 2500 and 3500, but the 3500 also has the option of the High Output derivative which produces 420 horsepower, 10 more than the 6.4-litre petrol Hemi V8 in the same range. In terms of torque, the High Output easily surpasses the others. It produces 1075 lb ft, well above the Standard Output’s 850 lb ft and the Hemi’s 429 lb ft. Slide of Chrysler Hemi: 425 horsepower (gross) Originally intended only for racing, the first Chrysler V8 officially called Hemi (and nicknamed Elephant) later became available in several Chrysler, Plymouth and Dodge road cars – including the aerodynamically adventurous Dodge Charger Daytona and Plymouth Superbird – and also in the Monteverdi Hai built in Switzerland. Measuring 7.0 litres, it was always officially rated at 425 horsepower gross, though in 1971 Chrysler and Plymouth also published a more realistic net rating of 350 horsepower. PICTURE: Dodge Charger Daytona Slide of Ford FE: 425 horsepower (gross) The FE V8 made its debut in the 1958 model year, when the 5.9-litre version was fitted to several models produced by the ill-fated Edsel brand. Two 7.0-litre v