It was powered by the 1,966 cc (120 cu in) Type 587/3, four-cam flat four-cylinder engine producing 198 hp (148 kW). In order to qualify to enter the 1964 FIA-GT race class, Porsche had to produce and sell a minimum of 100 units of a GT model as road cars to the public within the twelve months leading to the race. The 904 GTS (marketed as Carrera GTS) was produced for that purpose. At the end, Porsche produced 104 904s.
(Photos from noticias.coches.com)
(Photos from autowp.ru)
Towards the end of 904 production, however, a small batch of cars was also homologated and fitted with
6-cylinder (2.0 911-derived) engine with twin triple-choke Weber carburettors
and twin-plug ignition, thus raising the power output to nearer 210hp.
The race-prepared 904 GTS weighed just 655 kgs
and through 1964-65 achieved considerable international competition success.
(photos from maxted-page.com)