650 Horsepower Big Block Roadrunner: A Classic Muscle Car with All-Natural Power

650 Horsepower Big Block Roadrunner A Classic Muscle Car with All-Natural Power

If you’re a car enthusiast, you know that the term “muscle car” refers to an American high-performance car with a powerful engine, typically a V8, designed for straight-line acceleration. The Roadrunner was one of the most iconic muscle cars of the 1960s and 1970s, and it was produced by Plymouth, a division of Chrysler Corporation.

In this article, we’ll take a closer look at a 1971 Roadrunner owned by James, which boasts a massive 650 horsepower and a no-frills old-school approach.

History of Roadrunners

The Roadrunner was introduced in 1968 as an affordable muscle car that combined performance and practicality. It was named after the famous Warner Bros. cartoon character, and its marketing campaign was based on the cartoon’s catchphrase, “beep-beep.”

The first generation of Roadrunners was produced from 1968 to 1970, and it featured a lightweight body and a powerful V8 engine. The second generation, which included James’ 1971 Roadrunner, was produced from 1971 to 1974, and it featured a more substantial body and a more refined interior.

Purchase and History

James purchased his Roadrunner in 1975, right after he graduated from high school. It was originally equipped with a 383 engine, but over the years, James has upgraded it with a 440 and, eventually, a stroked 400 that now displaces 467 cubic inches.

The car was garage-kept from 1980 to 2010, and during that time, it underwent a complete restoration.


The engine in James’ Roadrunner is a work of art. It was built by Russ Bishop, a crew chief on a race team, and it produces a whopping 650 horsepower, all naturally aspirated.

It features Ross racing pistons, a forged bottom end, big cams, and a set of modified heads that have been carefully ported and polished. The carburetion is still old school, with a four-barrel Holley carburetor feeding air to the massive engine.

Transmission and Gearing

The transmission in James’ Roadrunner is a three-speed automatic Torqueflite 727 that has been beefed up with aftermarket parts and a shift kit. The gearing in the rear is a 3.55 ratio, and the car rides on 30-inch tires, which give it a top speed of around 140 mph.


The suspension on James’ Roadrunner is a modified stock setup with beefed-up torsion bars, sway bars, and Bilstein shocks. The rear suspension still uses leaf springs, but they are Mopar’s competition springs, which are designed for drag racing.

The car is primarily a straight-line performer, but it’s comfortable enough to drive on the street.


James’ Roadrunner is equipped with manual brakes and Wilwood discs on all four corners, providing ample stopping power to match the car’s impressive acceleration.

The exterior of the car is in great condition, with a classic B5 Blue paint job and the iconic “Roadrunner” cartoon decal on the rear quarter panels.


Inside, the car retains its original black vinyl bucket seats and center console, which have been well-maintained over the years. James has added a few aftermarket touches, such as an updated stereo system and a set of AutoMeter gauges to keep tabs on the engine’s vitals.

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As we take the car for a spin, it’s immediately apparent that this is no ordinary cruiser. The engine roars to life with a deep, throaty growl, and the car quickly builds speed as we hit the open road. The acceleration is strong and consistent, thanks to the massive amount of torque generated by the stroked 400.

Despite the car’s straight-line focus, the handling is surprisingly agile, with the beefed-up suspension keeping the car planted around corners. The steering is precise and responsive, allowing for quick changes in direction when needed.

As we wind our way through the hills surrounding James’ home, it’s easy to see why he’s held onto this car for so long. It’s a true testament to the golden age of American muscle cars, with its raw power, classic styling, and unmistakable presence on the road.


In conclusion, James’ 650HP Big Block Roadrunner is a true marvel of old-school muscle car engineering. With its massive stroked engine, upgraded suspension and brakes, and timeless styling, it’s a car that’s sure to turn heads and drop jaws wherever it goes.

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Whether cruising down the boulevard or tearing up the drag strip, this Roadrunner is a force to be reckoned with, and a true icon of American automotive history.

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