Let me translate for you. It is Peter Heck from Switzerland. He started building this car in December 1968, using a Skoda Octavia S from 1963. He modified the engine by using a twin carburator and a Felicia cylinder head in order to achieve around 55 hp instead of the former 40 hp. He worked almost 1900 hours and spent 2900 Swiss Francs on the car. It was registered for road use on June 15, 1971. The main part of the first article describes the work in detail.
By the way, according to a recent Skoda club magazine he is working on another self-built car right now. This time a Skoda 105 serves as the base.