The car was based on second-hand Tatra 613-2 model, which was originally modified by AMK Narex (since 1992 Narimex) who specialized in rescue operations.

This business had been set up by former racer, Cyril Svoboda, who was notorious for having adapted a Lancia Beta for rescue duties.

[1] The success of the T-623 resulted in Tatra carrying out further modifications, in collaboration with Narex and Kovoslužba rescue organizations.

[3] The car now featured a 3.8-Litre V8 engine producing over 300 hp (220 kW), and was capable of a top speed of 250 km/h (155 mph).

Its features included: a removable steering wheel and racing seats; adjustable and lowered suspension; upgraded braking system and tyres.