Meanwhile, chapter and verse on the twin-engined things... or at least this bloke's twin-engined things (he wasn't alone!):

Unusual two-engine racing car designed between the 60's and 70's in Cascavel (PR) by mechanic Deoclides Carpenedo. At least five versions were built, the first of them in 1967, even before the Fittipaldi brothers created their twin-engine Fitti-Volks. The first car was mounted on a DKW chassis, from which it received the two engines, one front and one rear mounted between axles, and coupled to them two Volkswagen gearboxes.

The car was driven by two accelerator pedals (!), One for each engine, two shift levers, positioned side by side (!!), one clutch pedal and one brake pedal. A car with such a configuration was evidently very difficult to control.

Seeking to make it more competitive, Deoclides was successively changing the mechanics and making it increasingly powerful. Until 1971 the twin-engine was introduced in four different configurations: DKW front and rear VW engine, front and rear VW engine, front VW engine and Simca V8 rear and finally Ford Corcel engine in front and Simca behind.

The main driver of the car and what best managed to "tame" him was the Paraná Valdir Favarin, who with him managed to win even the best Brazilian prototypes of the time. Favarin raced the twin-engine until 1974.

Thirty years later, in 2004, Deoclides decided to rebuild his prototype, "already very tired of racing and attacked by rust". The new car was also a hybrid, formed by the front half of a DKW chassis attached to the rear of a Kombi platform and equipped with two air-cooled VW engines and their gearboxes.

The set was covered by a glass-fiber-reinforced plastic cowl that, as if to honor tradition, had an unusual detail: a circular opening in the front enclosing the engine's cooling fan. The new Bimotor was inaugurated in 2009 by Favarin, a retired driver, penta-champion and two-time Brazilian runner-up of Sport-Prototype.
And a web page with the pics above plus two more:

http://www.lexicarbrasil.com.br/bimotor/

And to be honest, I would have been happy with more about single-engined cars!