In 1964 The Prince Motor Company had entered their new Prince Skyline GT to compete in the Second Japanese Grand Prix. Prince had gone to a lot of trouble preparing their Skyline race car. The Prince Skyline was a 1.5 litre 4 cylinder car, and wasn't about to win anything in it's current form. The Prince engineers decided to cut the front section of the Skyline off in front of the firewall and add an extra 200mm of length to the car, which would allow the the space to install their 2 litre overhead cam 6 cylinder G-7 engine from the large Prince Gloria sedan. This car, which was also fitted with triple 40DCOE Weber carburettors, easilly won the Touring car class of the race, yet finished second overall after having been beaten by a privately entered Porsche 904, which was a purpose-built race car rather than a modified road car. Buoyed by their success in the Touring car category, yet driven to do better after the disappointment of their loss to a fully-fledged racing prototype Porsche, Prince vowed to go one better next year. To do this they would need their own purpose-built prototype, and that was what they set out to build.
Shinichiro Sakurai was the head of engineering at Prince. The corporate philosophy at Prince allowed Sakurai to be daring with his ideas, as evidenced by the Prince Skyline GT project, which incidentally was turned into a full production model and was a great sales success for Prince. Prince gave Sakurai the go-ahead to design and build a racing prototype to compete in the 1965 Japanese Grand Prix. This was all uncharted waters for Prince, and for Japan as a whole, as no one had the expertise to design and build a prototype race car. Sakurai overcame this problem by buying a bare Brabham BT8 chassis on which to base the car, and then set about designing and building the body and mechanicals to fit to the chassis. The car they built was not unlike that of the Porsche 904 that had beaten them in the previous year. It was a low-slung aerodynamic two door rear-engined coupe with light weight alloy panelwork. The car was given the designation R-380.
Sakurai could have used the Prince G-7 engine in the car, but instead decided if you are going to all the trouble of building a purpose-built race car you might as well have a purpose-built engine to go with it. The engine he designed and built was called the GR-8 engine. The engine block of the GR-8 looked very similar to that of the G-7 engine, but was in fact a new design. The G-7 was a 'square' engine, with a bore and stroke of 75mmx75mm, while the GR-8 had a much shorter stroke with internal dimensions of 82mmx63mm. Fitted to the block was an alloy double overhead cam, four valve per cylinder, crossflow cylinder head. The new engine, which was fitted with three 42DCOE carburettors, produced over 200hp. Behind it sat a Hewland 5 speed transaxle.
The car was finished in 1965 and Sakurai and Prince were ready for the 1965 Japanese Grand Prix, except there was one problem, the 1965 Japanese Grand Prix ended up being cancelled. Prince now had a race car with nowhere to race it. Rather than let all that work go to waste Prince decided to wheel the R380 out onto the Yatabe Test Track and see if it could beat some speed records, which it did. The R380 not only beat the Japanese speed record it also beat several World E-class speed record by covering 50km at an average of 266.37kph, 100km at an average of 262.44kph and 200km at an average of 261.22kph.
A 1966 Japanese Grand Prix was announced, and finally Prince had a race to take their new toy to. They were confident of being able to beat the Porsche 904 with the world speed record breaking R380, but in the meantime Porsche had unveiled their new Porsche 906 Carrara 6. The Porsche 906 was significantly quicker than the 904. With 220hp compared to the Prince's 200hp, and with the 906 weighing 580kg compared to the R380's 660kg, it was not going to be plain sailing for Prince. Prince entered four R380s in the 1966 race, while there was only one 906 entered. Despite the performance disadvantage Prince won the race outright, and came second as well.
The R380 was redesigned in 1967 and became the R380-II. After the Prince Motor Company merged with Nissan in 1966 the Prince name was dropped and all previous Prince models became Nissans, including the R380-II, which would be known as the Nissan R380-II.
Length - 3930mm
Width - 1580mm
Height - 1035mm
Wheelbase - 2360mm
Weight - 660kg
Top speed - 270kph
Transmission - Hewland 5 speed Floor change
Model - GR-8
DOHC 6 Cylinder
Capacity - 1996cc
Bore & Stroke - 82x63mm
Power - 200hp@8000rpm
Torque - unknown
Compression - 11 : 1
Carburettors - triple 42DCOE Weber dual throat side draught
Final Drive - unknown
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