The Honda RA273 was a legendary Formula 1 racing car introduced by the Honda Racing team during the 1966 and 1967 seasons. It was built specifically to comply with the radical rule changes in 1966, which doubled the maximum engine capacity from 1.5 to 3.0 liters.

The RA273 was famous for its raw power and unique engineering. Unlike its predecessor (the RA272), which featured a transversely mounted engine, the RA273's engine was mounted longitudinally. The engine was designed by the legendary engineer Shoichiro Irimajiri. Producing over 400 hp at 10.500 rpm, it was by far the most powerful power unit of its generation. The engine featured an unusual 90-degree V-angle and four valves per cylinder. Another unique engineering detail was that the power drive to the gearbox was taken from the center of the crankshaft.

Although the engine was extremely powerful, the design was complex and heavy. Consequently, the car weighed around 740 kg, making it significantly heavier than its competitors.

Because the development of the new 3-liter engine faced delays, the car made its debut halfway through the 1966 season at the Italian Grand Prix.

While the RA273 frequently led races thanks to its immense straight-line speed, reliability issues and excessive weight prevented it from ever winning a Grand Prix. Its best results were a few podium finishes, including a third place for Surtees in South Africa (1967).

During the 1967 season, the RA273 was replaced by the lighter and more successful Honda RA300, which was built in collaboration with Lola.

 

The Honda RA302 was a Formula One racing car produced by Honda Racing, and introduced by Honda Racing France during the 1968 Formula One season.

The car was built based on an order by Soichiro Honda to develop an air-cooled Formula One engine. The magnesium-skinned car was entered in the Formula One race alongside the water-cooled, aluminium-bodied RA301 which had been developed by the existing Honda team and British Lola Cars.

At a time when the rest of the F1 grid was relying on water-cooled engines, Honda pushed to build an advanced, naturally aspirated 3.0-liter, 120-degree V8 air-cooled engine. Officially it rated at over 430 horsepower at 11.500 rpm.

The car had an avant-garde, pointy front nose designed for aerodynamic efficiency without a front-facing radiator.

It would only appear in one race, the 1968 French Grand Prix at Rouen-Les-Essarts, driven by Jo Schlesser. Schlesser was chosen to drive the RA302 because normal Honda driver John Surtees (who was the 1964 world champion and would finish second in that race) refused to drive it as he deemed it to be unsafe and labelled it as a "potential deathtrap". This was proven on lap three of the Grand Prix; Schlesser crashed at the Virage des Six Frères section of the circuit and the car came to rest sideways against a bank. The magnesium-bodied Honda and 58 laps worth of fuel ignited instantly, killing Schlesser and destroying the original RA302.

A second RA302 was built, with slight modifications, earmarked for Surtees to drive at the 1968 Italian Grand Prix, but he again refused to drive it. Honda decided to pull out of Grand Prix racing and did not return as a constructor until 2006 with the RA106. 

In 2012, the RA302 intended for Surtees at the Italian Grand Prix was on display at the Honda Collection Hall.