The Absolute Best 5 Muscle Car Motors of the 1960s
These Are The Greatest Muscle Car Engines Of The Swinging Sixties
Updated September 28, 2018
In only the last few year have engineers been able to leapfrog the performance of engines built 50 years ago, engines that have long since become legend, their presence in a restored muscle car not only bringing extra dollars on the auction block but plenty of oohs and aahs from onlookers poking their heads under the hood.
There have been rumors over the years that these engines have been severally underrated for a variety of reasons. In reality, when freshly rebuilt versions using 100% stock components have been run on a dynamometer, their output is consistent with what the factory stated.
Recall that the engineers of the 1960s could predict airflow through CFD (computational fluid dynamics), deliver fuel via a direct injection system that pulsed the output to assure the best possible mixture, computers that consistently monitored all engine functions that allowed maximum performance under the available condition, or any of the other tools and gizmos available to engines today.
The most these pioneers of performance had at their disposal was a flow bench, a dyno, but mostly their own experience and skill, yet they still created some of the most memorable motors in the brief history of the automobile. Click Next to view the list:
1965 Ford 427 FE Side Oiler
The famous side-oiler configuration of the FE (Ford-Edsel) block was developed for the Shelby Cobras as they moved up a class in international sports car racing. The engine was quickly adopted as the block of choice among all competitors because of the path of oil through the engine allowed it to rev above. 6500 rpm. Very few 427s made it into production cars and most of the those were intended for racing, particularly stock-based drag racing classes. Rated at 425 hp in Gross trim, output was consistent with its competitors. Ford even experimented with a SOHC version of the engine, but it was never installed in a production car. While the 427 designed as a race engine (and a very successful one winning the 24 Hours of Le Mans 24 fitted to the GT40 and the Daytona 500 with a Fairlane) it was a little too finicky to be a street motor, so the 428 was created to meet that need.
1966 Chrysler 426 Hemi
Chrysler had been playing cat and mouse with NASCAR for a number of years regarding the legality of the Hemi engine, which had as of yet not actually been delivered to a paying customer in a passenger car. By 1966 Chrysler had no choice and offered the Hemi in a number of different models, and not just performance cars. There were several plain-jane Coronet four-door sedans ordered with the “eleplant motor.” Displacing 7.0 L (426 CID), the engines were both massive and expensive to build, so only 11,000 were installed in passenger cars between 1966 – 1971. The engine produced 425 hp in “gross” form and 350 hp in “net” trim.
1969 Chevrolet ZL-1
To bypass corporate rules that limited engine sizes, racers used the special-order (COPO) system to get the cars they wanted. When ordering COPO 9560 you received a Camaro with an all-aluminum 427 CID ZL-1 big block. Unfortunately for us, just 69 ZL-1 Chevrolet Camaros were produced, but not surprisingly as each engine was hand-built and cost over $4,00, more than the cost of a base V-8 coupe. Though rated at 430 hp gross, the ZL-1 made 376 hp in its net configuration, not inconsistent with the output Chrysler was pulling from the Hemi.
1969 Ford Boss 429
Perhaps the best muscle car street engine of the era was the Ford Boss 429. Completely unrelated to either the 427 and 428, both which were based on the Ford FE block, the 429 was developed around the new 385 block (the name comes from its original crank stroke, not its displacement). It used four bolt mains, a forged steel crank and rods, and aluminum cylinder heads, which had a modified Hemi type combustion chamber topped by a used a single Holley four barrel carburetor mounted on an aluminum intake manifold. The engine wouldn’t fit in a stock Mustangs so the body shells were shipped to a subcontractor to modify. Little wonder only 859 were made.
1969 Ford Boss 302
The Ford Boss 302 was built for one purpose – to win the Trans-Am Championship against Camaro, Challenger, Barracuda, and Javelin. The small block V8 motor was created by mating the heads from the yet-to-be-introduced Ford Cleveland V8 to the a 4 bolt heavy duty block of the Ford Windsor. The heads are “tunnel-port” where the pushrod runs a straight path through brass tunnel in the intake runner allowing for better airflow, a design adopted from the 427 FE. Atop a taller, higher manifold was fixed a four-barrel carb. In stock form it produced 290 HP in “net” trim, only 60 hp less than the Hemi that 30% larger.
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