With Porsche leading Alpine-Renault by only three points before the season-ending RAC Rally, the championship went down to the wire.
Alpine-Renault's best result was then Andrew Cowan's fifth place, and Porsche took the title.
Porsche's Gérard Larrousse also picked up a point for sixth place.
The Alpine-Renault, driven by Bernard Darniche, also won the last Coupe des Alpes, but because the event ran with an insufficient number of starters (36 when the FIA minimum was 50), no points were awarded towards the championship.
The Fulvia 1.6 Coupé HF was driven by Simo Lampinen (35 points), Harry Källström (22) Sandro Munari (20) and Amilcare Ballestrieri (20).