Overview
Vauxhall's small rear-wheel-drive Chevette was transformed into a serious Group 4 rally car by Dealer Team Vauxhall and Blydenstein: the Chevette HS used a longitudinal 2.3-litre Vauxhall slant-four engine with a sixteen-valve head, stronger gearbox and a strengthened rear axle. It shared the compact GM T-car production architecture with the Opel Kadett but was not simply a 1.3-litre road hatchback wearing stripes.
The FIA lists Vauxhall Chevette HS 2300 as Group 4 form 649, 2,279 cc, effective 2 November 1976. There was, however, a period dispute about whether the necessary number of identical road cars and correct competition components existed for 1978 FIA eligibility; RallySport's specialist retrospective explains why early works head/gearbox combinations differed from the showroom HS. Consequently, an original homologation date does not mean every 1976 specification was freely eligible at every later international rally.
In 1979 Pentti Airikkala, navigated by Risto Virtanen, won the British Open Rally Championship drivers' title in the HS, including the Circuit of Ireland, Scottish and Ulster events. A third-place outright finish at the 1979 Swedish WRC rally was an international podium but not a WRC event victory. The HSR evolution, with much more composite bodywork and altered rear suspension, was homologated in April 1980. This later car did not win Airikkala's 1979 title, despite some secondary summaries combining HS and HSR under one badge.