In his new movie "Tucker, The Man and His Dream," Director Francis Ford Coppola spins a tale of post World War II optimism and salesmanship, when car-hungry Americans were for a time mesmerized by a succession of auto promoters of whom Preston Tucker was the gaudiest.

As Coppola tells the tale, Tucker was a genius of an automotive inventor who was done in by the Detroit establishment who were afraid of his competition.In reality, Tucker was no inventor, only a super promoter, a four-wheeled version of the instrument salesman in "Music Man.

Preston Tucker, as those of us old enough to remember pressing our noses up against showroom windows in 1945 will recall, cobbled up a glossy car out of automotive odds and ends. He packaged it with brass bands and models, sold a lot of dealerships, then went bust when his dream ran out of overheated air.

He probably believed in the Tucker Torpedo, but the car never had a chance because Tucker himself was long on dreams and enthusiasm but short on the ability needed to turn a dream into reality. He sold hopes, including his own, but built no solid foundation under the froth.

Tucker was a Detroit car salesman in the late 1920s. In 1930, the second year of the Depression, he was trying to move luxurious Pierce-Arrows in the suburb of Lincoln Park with little success. A car buff, Tucker went to the Indianapolis 500 that spring and stumbled across race car designer Harry Miller.

Miller was in financial trouble both because the Depression-era racing formula had been written to severely handicap the elegant, costly supercharged Miller cars, and because Miller was a dreamer and no businessman. He and Tucker hooked up to sell Miller engine designs to the Army Air Corps.

Miller engines had been worldbeaters on the track and in Gar Wood's speedboats held world water records, but the Army didn't offer any contracts to the Miller-Tucker Co.

Tucker, using Miller's well-known and respected name around Detroit, attempted next to revive The Marmon Motor Co., which had gone bankrupt in the Depression and eventually disappeared.

Next, in January 1935, Tucker went to Edsel Ford and sold him on the idea of having Miller put the new Ford V-8 engine into a team of Indianapolis cars which, Tucker said, would dominate the Speedway. Ford would get priceless publicity for its 1935 cars when racing versions with the same engine and radiator grille came in first, second and third, at least, and for only $25,000.

There was far too little time to build and test 10 racing cars of a brand-new design. As author Mark Dees tells in in his book "The Miller Dynasty," Tucker obtained another $50,000 from Ford, and Miller got to work. Ford eventually contributed heavily in engineering and production assistance and eight cars were finished of which four qualified.

The Miller-Fords were artistic cars, with advanced aerodynamics and design. Another year of testing might have made them winners, but the specially designed steering boxes had been improperly heat-treated. They were installed right over the red-hot exhaust manifolds and by the 145th lap all four had dropped out with steering failure.

Tucker's contribution was purely in salesmanship. A year later he rode a brand new Harley-Davidson knucklehead twin around the grounds at Indy as a salesman for that company - anyone with some cash. During the Miller-Ford preparations Tucker put his wife and daughter on the payroll, then took a liberal expense account for himself.

In 1937 Miller got Gulf Oil to sponsor a team of specially built racing cars for Indianapolis. For them Miller came up with disc brakes, the first ever used on an American car in modern times. A four-cylinder engine was tried and failed. Tucker later bought the cars from Gulf and at the beginning of World War II he proposed a joint venture with boat builder Andrew Higgins for high-speed landing craft, using Gulf-Miller engines, but that came to naught.

Next, Tucker came up with the idea of a high-speed combat car with a clear plastic machine gun turret, powered by a Miller engine to speeds of over 100 mph. The military set Tucker up in a plant in Ypsilanti, Mich., in 1940, to develop the turret, though the car was abandoned.

Tucker's war work supported other projects and the outline of a post-war Miller-designed passenger car may have sprouted then. Miller proposed a rear engine of flat, air-cooled design, something like the Volkswagen. It would have his disc brakes and other far-out refinements that came from Harry Miller's fertile but not terribly practical mind.

Miller became chief engineer of Tucker Aircraft Corp. and designed engines for a fighter to be known as the P-57. Miller was also designing a V-16 marine engine for the Navy.

Tucker, who never had any capital of his own, convinced the government that the XP-57 prototype with Miller engines was almost complete. He wrung $48,000 out of the Army and tried to get $60,000 more to keep that shoestring operation afloat. Unfortunately, inspectors from Washington reported the XP-57 only 25 percent done. Work came to a halt on Feb. 10, 1942, with Tucker owing $20,000 in back wages and material bills.

Miller died in Detroit in 1943, but his passenger cars lived on in Tucker's head. Tucker had a designer in Detroit draw up blueprints of the Miller ideas - one with individual torque converters at each wheel had to be dropped. The rear engine Tucker used was a existing air-cooled Franklin rather than a Miller.

To promote the Tucker Torpedo, Tucker entered one of the Gulf-Miller cars under that name in the 1946 Indianapolis 500, but the transmission failed during the race. The same car was run at Indy for Tucker as a promotion in 1947 and 1948 but finished neither contest.

Given Detroit's knowledge of Tucker's record, it is not surprising that the Music Man of the Motor City had to go out into the hinterlands and sell dealerships to raise capital for his auto venture.

Like the De Lorean and other failed auto ventures of more modern times, a untried auto did not appeal to enough American buyers to keep an assembly line going. Industrialist Henry J. Kaiser, with billions behind him, came closer than Tucker, but the Kaisers and Frazers went under too. Studebaker, Packard and Nash disappeared, not because Detroit did them dirt, but because auto making in the second half of the 20th century requires immense capital and staying power. Preston Tucker had the salesmanship, he could borrow the ideas, but he never had enough money or enough customers.