Rare, Experimental, and Horsepower Rich Muscle Car Engines from the 2024 Muscle Car and Corvette Nationals

Cubic inches compounded in the 1960s to create the greatest automotive arms race the world has ever known. Whether on track or the showroom floor, horsepower sold cars, and American manufacturers were out for blood deploying every bit of technology at their fingertips to best the competition. It was the era of “Win on Sunday, Sell on Monday.” And damnit you’d better win.

At the 2024 Muscle Car and Corvette Nationals, one of the many excellent exhibits featured rare and experimental engines, some of which ended up under-hood of race cars, while many were eternally entombed to R&D labs. Regardless, this was a celebration of innovation and was a truly unique vantage point of to just what ends manufacturers and privateers were willing to go to immortalize their brands in automotive lore.

Chrysler Dual-Plug 426 Hemi

This dual-plug Hemi is a great example of early engine innovation. The distributors mesh together just above the block deck and the the twin spark plugs help to better ignite the mixture in the Hemi’s combustion chamber, which has a uniquely large surface area. Racers found the additional spark plug to be worth horsepower through more complete combustion, a tradition that has remained even at the modern top fuel rung of drag racing.

Aluminum Big-Block Chevrolet Can-Am Engine

Brought by Daniel Boshears, this aluminum big-block Chevy was the heart of a Can-Am racer. An alloy oddity in an era where cast-iron was the cast weapon of choice, the big-block Chevy architecture with its high-flowing splayed-valve heads and massive displacement ceiling contributed to one of the most jaw-dropping and visceral race series of all time.

Oldsmobile W-43 32-Valve 455-cu.in. Big-Block

Under the hood of this Oldsmobile is one of Detroit’s finest performances. The 32-Valve W-43 455-cu.in. V-8 is inarguably one of the coolest Oldsmobile creations of all time. The particular engine shown has quite the story and you can read more HERE.

Ford 427 SOHC “Cammer” FE Big Block

If there was an engine nameplate with a ring in need of kissing, you’re lookin’ at it. The FE-based 427 Cammer is one of the most ambitious blue-oval outings ever and was a commendable technological awakening for Ford. With 427-cu.in., a lightweight block casting, single-overhead-cam heads, and a timing chain long enough to jump rope, the Cammer was a wild creation that, while mostly relegated to dragstrips courtesy of NASCAR’s banning, lives on to this day as an upper-crust power plant, and in its modular and Coyote branded descendants.

Chevrolet 427 Mystery Motor, Godfather of the Mark IV Big Block

While a quick glance would suggest another Chevrolet-orange big block, the engine at hand is far more significant. This is an early 427 “Mystery Motor” the development mule that paves the way for the Mark IV big-block. The splayed valves gave the cylinder heads the nickname “porcupine” and were a major improvement from the out-going W-motors “chamber-in block” design. Amazingly, almost no parts crossover between the mystery motor and subsequent Mark IV. Also noteworthy is the Z11 cowl-induction air cleaner.

426 Max Wedge Chrysler with Barney Navaro Cross-Ram, Quad-Quad Intake Manifold

In the glory days of drag racing, induction was everything and racers tried every combination of carburetors possible to maximize their combination’s performance at the track. This wild, Barney Navaro, cross-ram, “quad-quad” (terminology?) intake has real estate for four, Carter AFB carburetor. With each carb flowing 500cfm, that totals a whirlwind 2,000 possible CFM of air flow for the 426-cu.in. Max Wedge motor beneath it.

Rare Pontiac 400-Cu.In. Ram Air IV Dual-Quad, Cross-Ram Intake

According to its owners, this Ram Air IV Pontiac, originally purchased by Bruce Griffith, has a rare, 1-of-3, cross-ram intake that was given to Bruce by a Pontiac Engineer to aid in his racing endeavors. A few interesting things we noticed about the intake: The lower water bypass, where it would interface with the front cover is not machined, and the engine is utilizing spacers from the cylinder head ports to the intake manifold, suggesting the intake was originally designed for an engine with a significantly shorter deck height. Trans-Am maybe?

1,400hp McLaren-Built 694-Cu.In. Off-Shore Boat Engine

Easily the biggest engine in the building, this Mclaren-built–yes, that McLaren–displaced 694 cubic inches. At 6,000 RPM, with its blower at full song, it cranked out 1,400 horsepower and pushed an off-shore racing boat to 130mph. The ’80s were a weird time and the supercar manufacturer’s stint into large-cube pushrod motors for offshore racing certainly wasn’t the weirdest thing happening at the time.

Home-Built Double Overhead Cam Chrysler 331ci Hemi 1952 Indianapolis 500 Engine

This early 331-cu.in. Hemi with dual overhead camshaft conversion was quite-possibly one of the coolest engines in the exhibit. While destined for the brickyard and grand-prix fame, it was clearly a grassroots effort. The combination demonstrates some truly innovative concepts, such as the gear-driven cams that power off a central idler inside the lifter valley, and the early Hilborn fuel injection. Under the valve covers, dual cams, spinning on roller bearings in custom-fabricated aluminum housings actuate the valves. Above the valve cover, an instantly recognizable signature denotes a valvetrain legend may have had a hand in this wild creation.

Turbonique Rocket Engine

Nothing to see here, folks. Just a mail-order rocket engine that could have been yours in the 1960s. Sure, you may not be here to tell the tale if it was, but what a wild time–and way–to go racin’. At last year’s MCACN, the show held a special feature on the history of Turbonique rocket engines. Read more here!

Chrysler Round-Port 426 NHRA Pro Stock Hemi

This experimental D5-5 426 Hemi used round intake ports instead of the conventional rectangle shape. It was intended for NHRA Pro Stock drag racing and was a Tom Hoover/Harry Weslake collaboration. The block and head were cast wider and the intake valve angles were laid over for improved performance. Note the presence of dual distributors and spark plugs per cylinder as well as the fabricated tubular intake manifold. We’re not sure what’s going on with the spark plug wires, but assume they are of a copper core design for maximum spark energy. Know what they are? Let us know in the comments!

AMC 390-CU.In. Engine

How about some much deserved love for the American Motors Corporation (AMC). When this 390 hit production, it was a huge step-up for the company. The all-iron engine packed near big-block displacement, but do to advanced thin-wall castings, tipped the scales at a light-for-the-time 600lbs. Output was initially rated at 315-hp and 425 lb-ft of torque.

Ford Boss 429 Dual-Plug “Semi-Hemi” NHRA Pro Stock Engine

This unique, dual-plug Boss 429 Ford engine, owned by Tom Rosemann of St. Louis Missouri, was certainly an unexpected sight. Ignition is delivered via a magneto mounted in the standard distributor location, and a second magneto mounted to the timing cover and driven by the camshaft. The Boss 429, nicknamed the “Semi-Hemi” had an oblong combustion chamber, much like the Chrysler variant and we imagine the secondary ignition system was an era-typical Hail Mary for more complete combustion and any measurable advantage over the car in the next lane. Read more here!

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