The Ball-Stud V8 was intended to be Act II in Chrysler’s Hemi muscle-car story, but unfortunately, it never made it past the prototype phase. Here’s the story behind the interesting experiment.

Chrysler’s 426 Hemi was the king of the hill all through the ’60s muscle-car era, ruling the drag stips and drive-ins and more than holding its own on the NASCAR ovals. Still, the mighty Hemi was not without its drawbacks. With its twin rocker shafts and complex cylinder head castings, it was bulky, heavy, costly to manufacture, and expensive in the showrooms. The 426 Hemi was practically an exotic by mass-market standards, and no more than 11,000 complete engines were produced between 1964 and 1971.

As the 1960s were drawing to a close, Chrysler engineers went back to the drawing boards to craft a simpler, cheaper version of the Hemi. And while they were at it, they proposed to consolidate all the company’s big-block V8s—the 383/400, the 440, and the 426 Hemi—into a single, all-purpose engine family. Two displacements were initially planned, 400 and 444 cubic inches, and the project was given the official designation A279.

Of the handful of prototype engines constructed in 1968-69, only a single example is known to survive, Mopar experts say. This rare bear was owned by California drag racer Dick Landy for many years and eventually acquired and rebuilt by Mopar restoration expert John Arruzza. The block casting bears a 1969 date code.

As the photo suggests, the Ball-Stud Hemi is essentially the familiar big-block Chrysler V8, now sporting updated cylinder heads with canted, inclined valves operated by ball-mounted rocker arms. With a layout similar to the big-block Chevy or Cleveland Ford, it was significantly cheaper and lighter than the Hemi’s twin rocker-shaft system. The Ball-Stud Mopar checked in at 6.5 inches narrower and more than 100 lbs lighter than the 426. Photo above courtesy of John Arruzza via Pinterest.

With the 2.25-in. intake valves tipped 15 degrees and the 1.94-inch exhaust valves at 6 degrees from cylinder centerline, the A279 featured a tighter, shallower combustion chamber than the 426, but maintaining the familiar Hemi shape. Meanwhile, the twisted-from-perpendicular valve layout, rotated from around 12 o’clock to 2 o’clock, created what Chrysler engineers termed a “positive swirl” chamber.

Stamped, bathtub-style rocker arms, interchangeable on intake and exhaust, ran at an effective 1.6:1 motion ratio. Ports were sequenced IEIEIEIE, and while the D-shaped exhaust passages of the Ball-Stud head were considered inferior to the 426, the big, rectangular intake ports were said to flow better than older brother’s. Photo above courtesy of John Arruzza via Pinterest.

Chrysler originally planned to introduce the Ball-Stud V8 in 1972, but that never came to pass as the market for muscle cars and big-block applications in general was rapidly drying up. The project was shelved. Only this single prototype from the A279 program remains, which Mopar guru John Arruzza updated with a 481 CID stroker crank, a Holley four-barrel carb, and a sporty hydraulic cam grind, producing a healthy 500+ hp on the dyno.

The rare piece was then installed in a low-mileage ’69 notchback Barracuda formerly owned by Chrysler engineering boss Tom Hoover. A subsequent owner, Bob Solberg, donated the one-of-one Mopar car/engine combo to the National Auto and Truck Museum of the United States in Auburn, Indiana (NATMUS), where you can see it today.