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We all love a classic car with a bit of power, but unfortunately the history of the muscle car is littered with lies. Here’s a list of 8 muscle cars from Car News Central who were able to produce way more horsepower than advertised.
Chevrolet Chevelle SS 396
Huntington’s analysis identified the Chevrolet L-78 big block – as installed in the Chevelle 396 SS – as being under-reported by 25hp. The Chevelle was advertised as 375 hp @ 5600rpm vs 400hp @ 5600 rpm in the evaluations.
Mustang 428 Cobra-Jet
Most underrated in the group. Ford claims 335 hp @ 5200rpm vs Huntington’s analysis of 410 hp @ 5600rpm. Note a difference in engine speed between the two specs. The smaller 390 V8 with a 4-barrel carburetor was also rated at 335 hp.
Dodge Charger RT-440
Chrylser must have used the trick of underrating this engine by using a lower maximum speed. The 440 Magnum was tested to only 4600rpm which produced 375 hp but the engine actually produced a reliable 5400rpm and 410 hp.
Pontiac RAM Air 400
Produced and sold under the General Motors umbrella, the Pontiac RAM Air 400 capable of 366 hp @ 5100rpm. Despite the advertised horsepower, the car was actually able to produce something closer to 410 hp @ 5600rpm.
Ford Mustang Boss 429
Considered by many to be the ultimate muscle car of the classic era – not just because of its engine output but also its brakes and handling – was sold to the public as producing 375 hp @ 5200rpm, but was capable of 420hp @ 5600rpm.
Dodge 440 Six-Pack
The formula was simple, take a Chrysler big block and top it with three two-barrel carburetors with a total capacity of 1200cfm. The beauty of this for enthusiasts was that all this performance was available at a price about 50% cheaper than that of the Hemi engine. Chrysler told the public it was making 390 hp @ 4700rpm, but it was more like 430hp at 4600rpm.
Plymouth 426 Hemi
The elephant motor that Chrysler created for NASCAR racing was forced to be sold to the public in order to remain eligible for competition and so it became a legend both on and off the strip. The Hemi engines powered top fuel and funny car dragsters, and even today where there are zero Chrysler parts in these top-level NHRA motors, the architecture remains the same. The Hemi breathed extremely well so more horsepower was easily gained, increasing engine speed. The spec sheet said 425 hp @ 5000rpm but was more like 470hp @ 6000rpm.
Chevrolet Corvette 427 l-88
Chevrolet most definitely wanted to keep the I-88 out of the hands of street drivers and on the race track so power was rated at just 430hp @ 5200rpm. This was more like 480 hp @ 6400rpm, however when compared to the equivalent modern version of the ZL1, the Chevy ZZ427 crate motor produces 480 hp with a lower 10.1:1 compression ratio and pump gas. Based on that comparison, it’s thought that Huntington’s numbers are too conservative and it actually produced something around 500 hp.