As suggested by fellow auto artist Jon Sibal, (note the rear window decal) here is an early 70's (71 to be exact) Nissan Skyline 2000GT-R,
Fondly known as the Hakosuka (“box Skyline,” chassis code KPGC10), the 1971 Skyline was the first to wear the world-renowned GT-R badge—for gran turismo racer—signifying that this was no run-of-the-mill Skyline GT. The inspiration for the GT-R was an early race special based on a regular, previous-generation S50 Skyline 2000GT that credibly competed with a specially-constructed Porsche 904 GTS in the 1964 Japanese Grand Prix, finishing second, amazing everyone involved and giving Porsche a scare. Now, a bit of history: the Skyline originated not as a Nissan at all, but rather as the flagship of the Prince Motor Company. They developed the predecessor inline-six engines that powered the GT-R’s ancestors, and former Prince engineers ultimately designed the Hako’s S20 motor. In fact, the Hako itself started life as a Prince design, but Nissan purchased the company in 1966 and finished work on the Skyline. Nissan rightly realized the brilliance of the Skyline concept, kept the “Skyline” moniker around for successive cars, and continued to develop the engine—and that engine is magnificent. Displacing 2 liters and capable of revving to 10,000 RPM (virtually unbelievable in the era, when only Formula 1 engines could come close), the triple-carbureted engine produces 160 horsepower stock. The Hako’s lithe 2,400 lbs. weight and advanced rear semi-trailing arm independent suspension mean that it is a fast, sweet-handling car by any standard. Original 2000GT-Rs are extremely rare and highly prized, commanding six-figure prices in good condition.