There is something that I believe all of you are missing, and it’s a key point as to why the American Muscle Car is so legendary. Before you go comparing an American Muscle Car to anything made by Aston Martin, Jaguar or anything like that, you need to be aware of what the intention of these machines were. The key difference between the American Muscle Car and any modern sports car is that the Muscle Car was designed specifically for the youth and working class demographic. Can Aston Martin or Jaguar claim they have made performance cars specifically aimed at teenagers, and people working low wage jobs? I don’t think so…
To understand Muscle Car handling you also have to know about individual Muscle Cars. “Muscle Car” is often used as a broad term that encompasses many types of cars from the era that aren’t technically “muscle cars” like the Camaro, Challenger, Cuda and Mustang which are “pony cars”; or cars like the Corvette which is a sports car and Shelby Cobra which is a roaster. Actual “Muscle Cars” which are full size sedans and hard tops along the lines of Chevelle, Charger, Satellite/GTX and GTO. There is a great difference in handling ability between these types of cars, for example a Chevelle rides like a boat; it has soft suspension that provides a comfortable ride. The Camaro as a pony car (partially sports car) has a more rigid suspension, lighter and handles better… And the Corvette which has a lower center of gravity, lighter than the Chevelle and Camaro with it’s fiberglass body, and independent rear suspension makes it a superior handling machine over the Camaro and Chevelle. And to stack on top of that was tire technology of the time which further hampered the handling performance of any car. Bias ply tires would loose their “footprint” or traction surface as the tire tread warped during corners.
On power to displacement ratios, the actual numbers produced by Muscle Cars of the era are a bit of a mystery. For example the 1970 SS Chevelle with a 454 LS6 engine was rated from factory at 450 BHP and 500 feet pounds of torque, but this was using the SAE gross method. SAE gross is the engine on a stand without accessories like a full exhaust, air filter, AC and etc… Which means as installed these engines didn’t actually produce these advertised numbers, the 454 LS6 engine as installed would actually produce around the order of about 390 BHP estimated. In 1971 the Muscle Car output figured took a one-two punch between emission regulations and now the requirement to use SAE net method (engine on stand fully dressed, more accurate to “as installed”) and you’d see numbers drop from 400 to 320 as an example.
And addressing these super low figures produced by Super Chevy Magizine Chevrolet Muscle Car Dyno Wars and shows like Top Gear, it needs to be recognized that these tests were done with a chassis dyno where power loss through drivetrain (and other factors such as brake drag) can be upwards of 15% or more, while automotive manufacturers still use SAE Net ratings for their engines. How-To - Car Improvement | DIY Cars | Car Work | Car Care
But the Muscle Car engine isn’t exactly a lie, they’re just a “half truth” so to speak, the rumors that many muscle car engines were under rated has truth to it. Engines like the 426 Hemi, the 454 LS6, and the 427 CJ and countless others were actually capable of achieving numbers that surpassed their advertised rating without any modifications to the engine’s internals. For example, Chevrolet’s aluminum 427 ZL1 engine, famous in the COPO and Yenko cars. Rated at 425 HP, as installed closer to 375 HP, replacing the manifolds with headers jumped the engine up to 419HP, removal of the air filter, air pump and alternator put the engine up to 447 HP. Rejetting the carb, adjusting the timing and removing the exhaust pushed the engine up to 523HP.
Finally, fuel economy… I won’t argue against the fact that they’re gas guzzlers. But a person needs to consider how these cars were built, most Muscle Cars were built purely for acceleration and as such most had low gearing and almost none had anything like overdrive. Gasoline back then wasn’t as good as it is today either, it had a higher octane rating and lead but that was about it, today’s gasoline has additives which helps boost fuel economy. If someone were in the process of restoring a muscle car, and if they added an overdrive transmission and more reasonable driving ratios, as well as tuning the engine to run better with today’s fuel; it’s entirely possible to get a car that once had 8 MPH in it’s day into the high teens and even up to 20 MPG highway depending on the car.