Chrysler's 1955 300 coupe was America's first mass-produced 300-horsepower car and was its first big, brash, luxurious 300 "letter-series" model. The 300s had become a strong Chrysler image builder by 1961, when the new 300G model arrived as the America's most powerful car with its 375-horsepower V-8.

When the 1955 300 was introduced, the fastest, highest-horsepower American cars were the largest, most luxurious models because they mainly were bought by older folks. They had the most money and wanted luxurious interiors and lots of sheet metal around them. Size equaled power, and the 300 soon became known as a "gentleman's hot rod." The era of instant-millionaire rock stars and young computer industry entrepreneurs was in the future.

Count your blessings if your garage houses a 300G in excellent condition. No other 1961 American car compares to it. The 300G came as a $5,411 coupe and $5,841 convertible, making them Chrysler's most costly models. But a 300G coupe now is valued at $72,000 and the convertible is at $159,925 if in top shape, says the Collectible Vehicle Value Guide.

The first four 300 models had a Hemi V-8, but it was a heavy engine that was costly to build. Chrysler thus switched to a regular high-performance V-8 for the 1959 300E and other now-classic letter series cars, which ended with the 1965 300L Actually, the 380-horsepower 300E was three seconds faster to 90 mph than the 1958 380-390-horsepower 300D with its Hemi V-8.

Each new 300 after the groundbreaking 1955 model got the next letter in the alphabet as part of its designation, starting with the 1956 300B. (The letter "I" was skipped for 1963 to avoid confusion with the number "1.")

The first two 300 models, which dominated NASCAR stock car racing, came only as coupes and just had regular front bench seats because bucket seats were considered just for sports cars. But the sportier, dramatically restyled 1957 300C added a convertible and had individual front seats, besides a new torsion-bar front suspension for sharper handling and Chrysler's new TorqueFlite three-speed automatic transmission, which was the industry's best. The 1958 300D was virtually identical to the 300E.

The 300F had Chrysler's new unit body-chassis and was even sportier. It had four contoured seats, including self-activating swivel front bucket seats that swung to the side when a door was opened. The luxurious, high-quality interior had a front/rear center console and electro-luminescent instrument panel.

The 300F also had the first four-speed manual transmission offered for a post-World War II Chrysler. Unfortunately, it was a balky French unit that didn't like fast shifts. It was ordered for no more than 15 300Fs with the car's optional 400-horsepower V-8 -- although it proved its worth at speed runs in Daytona, Fla., where six 300Fs equipped with it had flying mile times between 141.5 and 144.9 mph.

One major 300F highlight was power-producing and imposing-looking ram manifolds for its 413-cubic-inch V-8, which had a standard 375-horsepower rating. Chrysler had been experimenting with a power-producing ram induction engine feature since 1952, and it had been used in racing. The 300F's carburetors were put on a wild-looking cross-ram manifold that put one air cleaner on each side of the engine. The stacks were 30 inches long and had to be crisscrossed to fit under the hood.

Putting carburetors on the ends of the tubes rather than in the middle provided a steady power increase along the engine's torque curve without the need for turbocharging or supercharging. A section of the inner manifold walls was removed to shorten the rams to a 15-inch length and create the optional 400-horsepower engine, mainly intended for Daytona-bound cars that ran in the Flying Mile event.

The 1961 300G was mechanically identical to the 300F but had styling revisions, although it retained the 300F's tall tailfins that ended in sharp points above deftly fitted taillights. The revisions included an upside-down trapezoid grille and canted, vertical quad headlights. A fake spare tire outline on the trunk of the 300F was eliminated, and Chrysler switched back to 15-inch wheels for the first time since 1956.

The interior was beautifully done in perforated leather, chrome, aluminum and steel, with a "control center" instrument cluster. Motor Trend magazine called the 300G interior "the finest in the industry."

The 300G's highlight also was the ram induction V-8. It had a race-style camshaft, heavy-duty valve springs, low back-pressure exhaust system, dual point distributor, low-restriction air cleaner, special spark plugs and dual quad carburetors. Bendix Electrojector fuel injection had been a costly $400 option for the 1958 300D, but technology didn't exist to make it reliable. It was ordered for only 16 cars, and most of them were converted to dual four-barrel carburetors.

Even the 300G's standard 375-horsepower V-8 produced far more power than Cadillac's 325-horsepower V-8 or the Chevrolet Corvette's optional 315-horsepower V-8. A 1961 Ford V-8 with 375 horsepower was offered, but its availability was extremely limited.

The 300G again set the pace at Daytona, hitting 143 mph for the Flying Mile event with the 400-horsepower V-8.

The 300G was offered with a new three-speed manual transmission with a floor shifter, which replaced the French four-speed manual gearbox. The new transmission was a truck-derived heavy-duty unit with an unsynchronized first gear. It mainly was put in 300Gs for auto magazine road tests, but it also was unpopular and few were ordered.

The 300G not only was fast, it handled amazingly well, especially for a big, heavy car. Reviewers described the car's high-speed stability, even with its old-style bias-ply (non-radial) tires, as "absolutely steady," "superb" and "glued to the road."

A 300 letter series car always was exclusive. Only 337 convertible and 1,280 1961 300G models were produced, although those numbers topped the combined total of 1,212 300F coupes and convertibles built.

The 300G was followed by the equally powerful but less flamboyant looking 1962 300H, which had a 4-inch-shorter wheelbase and no fins. While outstanding, it somehow lacked the sex appeal of the 300G.