The year is 1964. The place: Japan. Our subject is the Prince Motor Company, and they’re not going to take this affront lying down. Porsche’s 904 GTS just defeated Prince’s race-modified Skylines in their own backyard, and instead of getting angry, they’re going to get even.

[youtube]http://www.youtube.com/watch?v=Vdqk7Wn7nwo&feature=related[/youtube]
Cue the mental image of a montage sequence of passionate PMC engineers pouring over plans, wind tunnel data, and a clay model. Slowly, an entirely new car emerges, sharing nothing but the engine with any other Prince model. Nestled amidships is a new version of the excellent and race-proven G-7 motor, called the GR-8. An oversquare inline six of 1.9 liters, with a 24 valve DOHC head and triple Weber carbs, making a healthy 200 HP.
[youtube]http://www.youtube.com/watch?v=XwfjAXNQNC8[/youtube]
In the video above, Shinichiro Sakurai, who started as a chassis engineer for Prince and became the father of the Prince/Nissan Skyline series and who was involved with the R380’s development, starts up the R380. He looks powerfully affected by the experience.
The motor is backed by a Hewland 5-speed racing gearbox. Draped over the bespoke chassis is a sexy, aerodynamic closed coupe shape, with glassed in lights and a flying buttress roof arrangement. The entire package clocks in at 1455 lbs, giving a 303 hp/ton power to weight ratio. Impressive, Prince, but can it beat the Porsches?
[youtube]http://www.youtube.com/watch?v=PjHKNoi1EFk&feature=player_embedded[/youtube]
The Japanese Grand Prix was cancelled for 1965, so Prince couldn’t pit the R380 against the Porsches for another year. Instead of simply mothballing the R380, Prince let it loose on the track and demolished a series of land-speed class records. When 1966 rolled around, the Prince team had dialed the car in, which was fortuitous because Porsche had flown in three of their brand new tube-framed 906 racers to replace the box-framed 904s of the previous season. This was a troubling development for the Prince team – the R380 was really designed to compete against the 904, powered by the roller-bearing 4-cam motor from the hottest 356. The 906 was much more powerful than the 904, sporting the 220 HP flat six, lifted and modified from its home in the new-for-1966 911S. The 906 was also much lighter than the R380, weighing in at only 1278 lbs. On paper, the 906 looked like a shoe-in.
However, Prince had a secret weapon – the track itself. The ’66 race took place at Fuji Speedway, a new racecourse with a notoriously dangerous banked turn. As Vic Elford, an Englishman driving for Porsche at the time (and who may have driven a 906 in the race, although I haven’t confirmed this either way), described it:
“In 1969 I spent two months in Japan doing a test contract for Toyota and their Toyota 7 (5 litre V-8), which along with a big Nissan (6.3 litre V-12), was destined for CanAm. My last testing and then the subsequent Sports Car GP were at Fuji, but the track was run in a clockwise direction. The reason that banking was so horrific, was that at the end of the straight we went over a blind crest at around 190/200 mph and dropped into the banking. At other tracks (Daytona, Monthlery, etc.) you climb up the banking. One of the results was that although there were many brave Japanese drivers there were not too many with great skill and the death toll from that one corner was horrendous. To such an extent that the big GP 7 cars were then banned in Japan and thus, neither Nissan or Toyota ever made it to CanAm.”
How much of an advantage this gave Prince is subjective and unclear. What’s not subjective is the result: four R380s faced off against the three Porsches, and the R380s finished first (Giichi Sunako), second (Hideo Oishi), and fourth in front of their German competitors. In the face of a technically superior challenger, with significantly more experience in both racing and advanced engineering, the Prince R380 had won the most important race in Japan. It was also the last time a Prince would race under that name.

Prince merged into Nissan that same year, and rebadged as a Nissan R380-II it only achieved 2nd in the ’67 race as Porsche took the victory. Later developed into the R381 (sporting a 5.5 liter Chevy V8), the car won the 1968 JGP, and the following year it won the same race as the R382, packing a Prince-developed 600 HP 6 liter V12. The final iteration of the original R3XX cars was the R383, which had the same motor as the R382, making a whopping 700 HP and inspired by Can-Am aerodynamics. With the cancellation of the 1970 race, the R3XX program was finished.
The Prince R380’s 1966 win can be considered perhaps the greatest moment for the Prince Motor Company, and luckily their commitment to sporty cars and talented engineering staff transferred over to Nissan, who allowed the Skyline series to flourish under its new master.
Wikipedia, Japanese Nostalgic Car, Supercars.net