By Dean Larson

At an initial glance, the RSK looks a lot like the celebrated 550 Spyder, and it’s easy to see how it could be mistaken for one with its telltale silver paint and wide-five wheels. But the RSK wasn’t dubbed the 550 RSK. It was given completely new nomenclature because it was a completely new design, crafted with all the lessons learned perfecting the 550 Spyder.

Like the 550, the RSK was based on a tubular space frame in a mid-engine, rear drive layout. The 550’s 1.5-liter Type 547 “Fuhrmann Engine” was also used, which made 142 hp initially, before being increased to 1.6 liters and 160 hp. Up front, the RSK used a torsion bar suspension design, while a Watt’s-Link and coil springs were used in the rear. Sources disagree on to meaning of the RSK nomenclature; with some claiming the K refers to the shape of the new front suspension, and others pointing to the shortened wheelbase, “Kurz” in German. The RS designates Rennsport, meaning motorsport in a simple translation. Unlike the 550 Spyder, zero production or customer versions of the 718 RSK were built.

This spectacular 718 RSK replica for sale on BringaTrailer.com was constructed by Thunder Ranch and has been driven less than 800 miles since. The car is built on a Beck-designed chassis and a mid-mounted VW 2,275 cc engine with Weber carburetors. The bodywork on the RSK is hand-laid DPCD polyester, which is mounted to the chassis using adhesive and rivets.

While the bodywork truly leaves nothing to be desired on the RSK, it’s the detail work that has us charmed. The squeaky-clean wide-five wheels and CNC hubs take the RSK up a notch, and give it that much more curb appeal on the dealer’s showroom floor. The interior is also nicely furnished, with red vinyl upholstery, a Nardi Torino steering wheel and the bare essential instruments and controls on the dash.

If there’s one nock against this RSK, it’s the windscreen. Given the original’s racer-only status, it was built with a slim, wrap-around windscreen. This car is fit with a standard 356 Speedster-style windscreen, which is without a doubt easier to source.

The 718 RSK is one of the least common Porsche replicas on the market, making them difficult to value. A well done fiberglass RSK can sell for over $50,000, while rough and less honest cars can get as little as $20,000. The Thunder Ranch replica is well respected, and shows very well. For those reasons, we’d expect a sale to happen around $50,000 to $55,000.

See the seller’s ad here on BringaTrailer.com.