It was comparable in size and mechanical specifications with the new Opel Kadett released a year earlier in continental Europe.
The Viva and Kadett were sold alongside each other in many markets.
The automatic Viva HB was offered from February 1967, and fitted with the ubiquitous Borg Warner Type 35 system.Cars of this size featuring automatic transmission were still unusual owing to the amount of power the transmission systems absorbed: in a heartfelt if uncharacteristically blunt piece of criticism a major British motoring journal later described Viva HBs with automatic transmission as "among the slowest cars on the road".A more luxurious SL (for Super Luxury) variant appeared in June 1965.Engines were available in two states of tune: entry level models came with a power output of 44 brake horsepower (33 k W), while the Viva 90, introduced in October 1965, had a higher 9:1 compression ratio and produced 54 brake horsepower (40 k W).The front crossmember (steering, suspension and engine mounting) assembly from the HA became a very popular item for DIY hot rod builders in the UK, due to its simple self-contained mechanics, similar to older designs such as those from the 1930s, and ability to accommodate much larger engines within its span.
The assembly featured a double wishbone/vertical telescopic dampers suspension design in combination with a transverse leaf spring attached to the front crossmember at its centre position and the entire unit could be removed and adapted to another vehicle.
The Viva HB inherited engines, but little else, from the HA.
along with other Vauxhall models of the time and very few of this model remain – one of the main problem areas being the cappings along the top side edges of the luggage compartment badly corroding and allowing water to enter, consequently leading to severe structural corrosion in the luggage-compartment floor area.
The availability of two engines and three trim options enabled Vauxhall to offer six Viva variants in some markets.
90 models came with front disc brakes, while SLs featured contrasting bodyside flashes, a criss-cross chrome plated front grille, full wheel covers, three-element round tail lights and better interior trim.
(For similar reasons the Jaguar IRS assembly was often used at the rear of these custom cars).