Christopher Runge builds custom cars at his company Runge Cars in Alexandria, Minnesota. Christopher’s newest creation is a 780 kg (1719 lb) mid-engine supercar called the Runge R3. The power plant for the R3 is an air-cooled 5.3 L “Hetzer” flat-eight. The motor was developed with help from Swindon Powertrain and air-cooled specialist Sol Snyderman. The motor features a 102.7 mm bore, 80.4 mm stroke, 12:1 compression, and 9,000 rpm redline. It will be a bolt-in replacement for the Porsche M64 flat-six. Full engine specs and pricing is expected later this year.
Source: Runge Cars FB page
It would be nice to see and explodes view showing the DOHC configuration. As it looks more alike a SOHC from the outside.