[4][5] In order to replace the by now old model 124 Sport Coupé, in 1972 FIAT started the X1/20 project, whose presentation was scheduled for the Turin Motor Show in 1974, entrusting the study of the line to Pininfarina and construction of the chassis for the newly acquired Abarth.
However, the management of the Italian company was rather reluctant to list a car with a racing vocation; this is also in the light of the results obtained by the latest two sports models 128 Coupé and X1/9, characterized by high engineering and construction contents, but warmly welcomed by the market.
Both the appearance of the bodywork and the technical configuration "all behind" (engine in the rear position, as well as the traction) anticipated those of the future Lancia Beta Montecarlo, albeit with important differences.
The engine is derived from the six-cylinder 3.200 of the Fiat 130, which was suitably developed by Abarth by increasing the displacement, strengthening the camshafts, and varying the fuel system with the inclusion of three Weber 48 IDF double-barrel carburetors.
As already mentioned, the engine was mounted at the rear, but it was necessary to insert it in a longitudinal position in order to be able to use the gearbox - differential unit produced by ZF, of the same type already used to equip the De Tomaso Pantera.