Kellison Astra X-300 GT: The Forgotten American Dream Car Built by Hand

Renegade Beauty - There’s something magical about the golden era of American automotive ingenuity. It was a time when ambition outpaced resources, and creativity was the most powerful tool in a builder’s garage. Among all the fascinating stories from that era, one stands out—not for its corporate polish or big-name pedigree, but for the vision of one man and the car that carried his dreams forward: the Kellison Astra X-300 GT.

The Astra X-300 GT (pictured here as a 1967 model) was the natural evolution of the Kellison J-4—more refined, sleeker, and noticeably more user-friendly. (Picture from: Carbuzz)

Born out of post-war optimism and a hunger for personal innovation, the Astra X-300 GT began as the vision of Jim Kellison. A veteran of the Korean War, Kellison returned home not with the desire to join the corporate ranks, but with a bold plan—to create a lightweight, powerful car that enthusiasts could build themselves. His weapon of choice? Fiberglass. A material already gaining popularity thanks to the Chevrolet Corvette, fiberglass allowed for exotic designs without the heavy burden of steel.

Jim Kellison is seen here with the J-4 Coupe, his company’s first production car launched in the late 1950s, which was sold both as a kit and turnkey model—most notably through Allied Fiberglass under the name Astra X-300 GT. (Picture from: Pinterest)

Kellison launched his own company in the 1950s and quickly made a name for himself among American kit car builders. His original J-series designs turned heads for their futuristic looks and performance potential. But as the market evolved, so did his creations. The Astra X-300 GT was the natural evolution of his earlier J-4 model—refined, sleeker, and more user-friendly.

The Kellison Astra X-300 GT (pictured here as a 1967 model) received subtle yet impactful updates, including a reshaped grille, smoother contours, and a more refined silhouette. (Picture from: Pinterest)

This updated model featured a slightly taller roofline—just two extra inches, but enough to dramatically improve comfort and visibility. The body received subtle but effective changes: a reshaped grille, smoother contours, and a more elegant silhouette. It was a design that not only looked fast standing still, but also promised a visceral driving experience once unleashed on the open road.

The Kellison Astra X-300 GT (pictured here as a 1967 model) featured a roofline raised by just two inches—subtle, yet enough to significantly enhance comfort and visibility. (Picture from: CurbsideClassic)

What made the Astra X-300 GT truly versatile was its compatibility. Builders could mount the body onto the proprietary Astra chassis, based on Kellison’s own designs from the 1950s, or opt for more accessible options like the 1955–1957 Chevrolet or Corvette chassis. The latter choice was especially popular, allowing for easy integration of the factory-installed V8 engine, transmission, and suspension systems—saving time and ensuring performance from the start.

The Kellison Astra X-300 GT (pictured here as a 1967 model) cabin fitted with black bucket seats, racing seatbelts, a custom steering wheel, and vintage toggle switches that feel lifted from a jet cockpit. (Picture from: CurbsideClassic)

Each X-300 GT built was a reflection of its maker. Some were masterfully completed, others left unfinished in garages, and many were customized beyond recognition. Records are fuzzy, and exact production numbers remain unknown. What’s certain, though, is that every surviving example is a rare piece of handcrafted automotive art. Over the years, some have even been misidentified as Kellisons when they were technically Astras, further adding to the mystique.

The Kellison Astra X-300 GT (pictured here as a 1967 model) powered by a potent 355 cubic inch small-block V8 paired with a four-speed manual transmission. (Picture from: Vintage ARV in Facebook)

The powertrain options varied, but one known restored example features a potent 355 cubic inch small-block V8 paired with a four-speed manual transmission. With less than 25,000 miles on the clock, it’s a time capsule wrapped in silver metallic paint and fitted with black bucket seats, racing seatbelts, a custom steering wheel, and vintage toggle switches that feel lifted from a jet cockpit. It’s a reminder that this wasn’t just a car—it was an experience.

The Kellison Astra X-300 GT (pictured here as a 1967 model) was a design that not only looked fast standing still, but also promised a visceral driving experience once unleashed on the open road. (Picture from: CurbsideClassic)

What was once considered a niche curiosity has now gained mainstream respect. Cars like the Astra X-300 GT, once ignored or dismissed as garage-built oddities, are now celebrated at prestigious events like the Pebble Beach Concours d’Elegance, sharing the lawn with Italian exotics and pre-war legends. Their value isn’t just in rarity, but in the story they tell—a story of independent spirit, hands-on craftsmanship, and pure automotive passion.

For those who love machines that break the mold and celebrate individuality, the Kellison Astra X-300 GT offers a glimpse into a unique chapter of American car culture. It may not have rolled off a mass-production line, but every curve, every bolt, and every roar of the engine speaks to a time when dreaming big and building it yourself was more than enough to turn heads. *** [EKA | FROM VARIOUS SOURCES | SILODROME | CARBUZZ | CURBSIDECLASSIC | PINTEREST | VINTAGE ARV IN FACEBOOK ]

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