This is a modern recreation of the Porsche 645 from the mid-1950s, a racing prototype that was a link between the earlier Porsche 550 and the later 550A and 718 RSK.
Just one example of the 645 was made, it was destroyed in an accident in 1956, and burned down to its chassis in the ensuing fire. This 645 recreation was built from the ground up by Porsche specialist Hardt Classics referencing factory blueprints, and it’s now being offered for sale in unfinished form.
Fast Facts: The Porsche 645 “Mickey Mouse”
- The Porsche Type 645, nicknamed “Mickey Mouse,” was a one-off mid-1950s prototype developed as a potential successor to the 550 Spyder. It aimed to reduce weight and drag with a new spaceframe chassis, slightly smaller dimensions, and a magnesium body, with a total weight of around 550 kgs, powered by Porsche’s 1.5 liter four-cam flat-four.
- Designed under Egon Forstner with input from Ernst Fuhrmann and Heinrich Klie, the 645 introduced experimental cooling and suspension systems. It had integrated oil cooling through the bodywork and revised front and rear torsion-bar setups, this all seemed to offer improvements on paper but the suspension caused unstable handling during real-world high speed testing.
- The sole prototype debuted during Nürburgring practice for the 1956 1000 kms race and later ran at Solitude, finishing fourth under the name “550 Spezial.” At the AVUS race that September, driver Richard von Frankenberg crashed at high speed – the car burned completely, permanently ending the 645 project.
- The car you see here is a modern recreation built by Hardt Classics in Australia to faithfully replicate the 645 using factory blueprints. Constructed with a tubular steel frame and aluminum body, it includes 356 Carrera GT drum brakes and a four-speed gearbox but lacks the four cam engine.
History Speedrun: The Porsche 645 RS “Mickey Mouse”
The Porsche Type 645, sometimes referred to as the 645 RS or by its nickname “Mickey Mouse,” was an experimental racing prototype developed in the mid-1950s as a possible successor to the wildly-successful 550 Spyder. It was conceived by Porsche’s engineering team, including Egon Forstner as project lead with contributions from Ernst Fuhrmann and Heinrich Klie, and based on the lessons learned from the 550 program, the 645 represented an ambitious attempt to reduce weight, improve aerodynamics, and refine the car’s mid-engine handling characteristics.
Here we see the only Porsche 645 that was completed being driven by Richard von Frankenberg in 1956. Image supplied by Porsche AG.
Though it never advanced beyond a single prototype, the 645 played a role in shaping the evolution of Porsche’s later racing cars, including the 550A and the 718 RSK.
The Type 645 began with a shortened and narrowed 550 chassis that was later replaced with a new tubular spaceframe design. Engineers were aiming to reduce the car’s frontal area and overall mass, ending up at a wheelbase of roughly 2,000 mm – shorter than the 550 – and a narrower track by about 100 mm in front and 140 mm at the rear.
The body was hand-formed from magnesium alloy to minimize weight, and the total weight was approximately 550 kgs, making it slightly lighter than the earlier 550 Spyder. The car’s compact form, combined with its carefully considered aerodynamic bodywork and integrated cooling systems, was designed to deliver better top-speed performance (through reduced weight and drag) even though it used the same engine.
The Porsche Type 645 Specifications
Power came from Porsche’s Type 547 “Fuhrmann” four-cam flat-four engine, displacing 1.5 liters and producing 135 bhp at 7,200 rpm with approximately 145 Nm of torque at 5,900 rpm. This engine, best-known for its complex double-overhead-camshaft-per-bank layout and gear-driven cam system, was already a proven race winner in the 550 series.
The front suspension of the 645 consisted of upper and lower trailing arms with transverse torsion bars and tubular shock absorbers, while the rear featured a unique trailing arm system with transverse torsion bars and lateral links.
Aerodynamics and cooling were critical areas of experimentation with the 645 – the front panel acted as an oil cooler, with hollow internal passages rather than a separate duct, while air vents in the rear deck directed flow to the carburetors and the engine bay. These design changes contributed to the car’s unusual appearance and were part of Porsche’s early exploration of integrated aerodynamic cooling – a philosophy that Porsche would continue to evolve in later cars.
This is a modern recreation of the Porsche 645 from the mid-1950s, a racing prototype that was a link between the earlier Porsche 550 and the later 550A and 718 RSK
Testing for the 645 began in late 1954, with the prototype completed and publicly tested by 1956. Its first major appearance came at the Nürburgring during practice for the 1000 km race in May. Although promising on paper, drivers quickly found the handling unpredictable. Its reduced track width and short wheelbase made it twitchy at speed, quickly earning the derisive nickname “Mickey Mouse” from journalist and Porsche driver Richard von Frankenberg.
Despite this, Frankenberg drove the car competitively at the Solitude circuit in July of 1956, finishing 4th in an entry listed as a “Porsche 550 Spezial,” which most historians now identify as the 645 prototype.
The Crash And The End Of The 645
The car’s ill-fated final on-track appearance came at the AVUS race in Berlin on September the 16th, 1956. During the race Frankenberg lost control on the steep banking and crashed violently, the car flipping over the embankment and catching fire where it landed on the other side. Frankenberg was thrown clear and he survived with non-life threatening injuries, but the prototype was destroyed beyond repair in the ensuring fireball.
Porsche subsequently terminated the program, deciding to focus on refining the proven 550 platform rather than pursuing the 645 concept further.
Although it was short-lived, the 645’s engineering ideas directly influenced Porsche’s next generation of competition cars. Its lightweight construction, spaceframe chassis, and aerodynamic lessons helped shape the design of the 550A and eventually the 718 RSK, both of which achieved a notable series of international successes.
The Porsche 645 “Mickey Mouse” Recreation Shown Here
This 645 recreation was built from the ground up by Porsche specialist Hardt Classics referencing factory blueprints, and it’s now being offered for sale in unfinished form.
The car you see here is a Porsche 645 recreation that was built by the Porsche specialists at Hardt Classics. They built it using original Porsche blueprints as a reference, and it has a lightweight tubular steel spaceframe chassis, as well as a hand-finished aluminum body.
It has front drum brakes from a 356 Carrera GT, a 4-speed manual gearbox, and many other parts, though it is currently missing an engine – in order to do the job properly it’ll need a Porsche Type 547 “Fuhrmann” four-cam flat-four, though these don’t come cheap.
It’s now being offered for sale out of Victoria, Australia on Collecting Cars, and it comes with a manufacturer’s authenticity certificate issued by Hardt Classics and an ignition key. If you’d like to read more about it or place a bid you can visit the listing here.
Images courtesy of Bring a Trailer
Articles that Ben Branch has written have been covered on CNN, Popular Mechanics, Smithsonian Magazine, Road & Track Magazine, the official Pinterest blog, the official eBay Motors blog, BuzzFeed, Autoweek Magazine, Wired Magazine, Autoblog, Gear Patrol, Jalopnik, The Verge, and many more.
Silodrome was founded by Ben back in 2010, in the years since the site has grown to become a world leader in the alternative and vintage motoring sector, with well over a million monthly readers from around the world and many hundreds of thousands of followers on social media.
