Introducing The Ball Stud HEMI, Chrysler’s Mystery Mini Elephant

Images: Mopar Action

What more needs to be written about the 426 HEMI? Yeah, we know King Kong absolutely killed in NASCAR in 1964, and we know a well-tuned Street HEMI was the one to beat from 1966-through-’71. And if you don’t know that a ’71 HEMI ‘Cuda rag top was the first million-buck muscle car, then you must’ve been drinking too much Bow Tie bug juice.

However, the Street HEMI was not the end of Chrysler’s HEMI development – what was Chrysler planning before emissions, insurance, and the like put an end to the first muscle car era? It turns out that the “Ball Stud” HEMI hints at the direction in which Chrysler was headed.

When Chrysler replaced the first-generation HEMI in 1958, it was with the new B-series Wedge. First introduced as a 350 in 1958, it eventually became more famous as a 383, which ended up being the standard motor for the Road Runner from 1968-through-’71.

A year later in 1959, the same basic design was introduced with a raised deck and christened “RB.” Two RBs debuted that year, a 413 and a 383, but the latter didn’t last past 1960 and should not be confused with the B-series 383.

In 1968, while Plymouth was introducing the Road Runner and Dodge was debuting a gorgeous new Charger, Chrysler engineers were busy using their slide rules and thinking about future horsepower.

The Street HEMI represented everything that was great about America, but it was a costly and complicated motor to produce. Although the Street HEMI’s raison d’être was for homologation for sanctioned racing, the limited production nature of the motor made it a thorn in Chrysler’s fiscal side. Hence, Chrysler engineers began to devise how they could reduce the complexity of building three different-yet-similar big block motors while producing HEMI-like power.

Thus began the development on the A279 engine program, otherwise known as the Ball Stud HEMI.

The most noticeable aspect of the Ball Stud HEMI was due to its canted valvetrain, a configuration made famous by the “Porcupine” Mark IV Chevy big block. However, the rocker arm arrangement is what gives this motor its unofficial nickname, as it eschewed the rocker shafts of the typical Chrysler V8 for a stud and ball arrangement.

In an article in Issue 1, Volume 1 of High Performance Mopar magazine, it’s described as “a stud that is anchored to the head holds the rocker in place between the pushrod and valve. A locknut and ball arrangement is threaded down on the stud to preload the rocker arm against the pushrod and give the rocker something to pivot against.”

To give you more of a Mopar-centric idea, the valve arrangement is reminiscent of the A-series “polysphere” 318, a motor that found popularity in hundreds of thousands of American-spec Mopars through 1966.

The canted valve arrangement couldn’t match the efficiency of the Street HEMI’s but, from a efficiency/cost quotient, it was an excellent choice. And in keeping with the cost and streamlining considerations that led to the creation of the A279 program, the valves were the same size as the Street HEMI’s. However, they were not installed through the middle of the valve cover a la Street HEMI but rather in a more conventional manner.

The foundation for all these ingredients was the B-series block, so that meant engineers had to make do with two-bolt mains. On top, a dual plane manifold was developed to be used with a Carter Thermoquad, which eventually appeared on the 340 LA-series small block in 1971. And even though the standard B-series casting was being used, plans were made to offer the Ball Stud HEMI in both 400 (a bored 383 that eventually debuted in 1972 in the Road Runner and Charger) and 440 sizes, even though the 440 previously had been an RB motor with the raised deck.

With Chrysler’s crystal ball suggesting the impending death knell for high performance cars by 1972, they decided further development wasn’t justified, and the A279 program was killed sometime before the end of 1969.

Today, two examples of this experimental performance motor are known to exist out of an estimated 12 built. For years one of them was owned by cigar-chompin’ “Dandy” Dick Landy, which he sold to famed builder John Arruzza. John completed the motor (some parts needed to be made from scratch) while beefing it up for more performance. The motor later had a new owner, who subsequently placed it on eBay in 2008. After that, the scent trail disappeared, but Mopar people are a resourceful bunch and it’s likely that the whereabouts of A279 is not a secret.

About the author

Diego Rosenberg

Diego is an automotive historian with experience working in Detroit as well as the classic car hobby. He is a published automotive writer in print and online and has a network of like-minded aficionados to depend on for information that's not in the public domain.
Read My Articles

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