Mazda Motors Corp.'s introduction of its 1993 626 model at the Chicago Auto Show was more than just a new-car showing. It illustrated the trend of the world's automotive industry for the decade of the 1990s.While bearing the name of a Japanese automobile manufacturer, the all-new 626 will be built exclusively in Flat Rock, Mich., by a United Auto Workers work force. And the car will have a domestic content in excess of 75 percent.When it comes on the market, it is expected to be classified by federal agencies as a domestic automobile, and be required to meet domestic corporate average fuel economy standards.It won't be in Indianapolis Mazda agencies until spring. Duke Gold, president of Speedway Mazda, saw the car at a dealer preview. He looks for the sedan to appear sometime during May.The 626 is four-door with distinctive styling and engineering features, particularly in the power plant, where there is a four- cam, 24-valve V-6.As Mazdas go, and they go quite well, the car is a pretty slick set of wheels. Available in three models, an entry level DX, an upgraded LX, and the top-of-the-line ES, the design shares a heritage with Mazda's luxury car, the 929 sedan."It looks like a smaller version of the 929," Gold said. "They've made the features better than past 626s."I especially liked the trunk design. It goes real deep, and the lid opens almost down to the bumper for easier loading."Aerodynamics obviously is the name of the game. The 626, like the daring young man on the flying trapeze, is styled to fly through the air with the greatest of ease.By lowering the hood and cowl, Mazda engineers have reduced the coefficient of drag, or air resistance, to 0.3l. The company says that is better than the two top-selling vehicles in the same market segment.The wheelbase of the new sedan is 102.8 inches, 1.4 inches longer than its predecessor. Despite its increase in size, it has a smaller turning radius than the 626 it is replacing.The company was mum on specifications at its San Francisco dealer showing, but it did say the increase in overall length has resulted in greater headroom and legroom for both driver and passengers. The cabin thus offers a less fatiguing environment for long drives.This cabin effect exemplifies the coming styling in automobile design, a theme called cabin forward. The windshield and cowl have been moved forward, and the rear window moved back to add interior room."The seating makes you feel like you're in a 929," Gold said.The new 24-valve V-6 is featured in the top-flight 626 ES sedan. That's not unexpected, in that a four-cam, four- valves-per-cylinder V-6 is more expensive to build than the 2.0-liter, l6- valve, dual-cam four-cylinder engines that are in DX and LX series.Gold thinks the exotic engine may run an additional $1,000 to $1,500."They wouldn't tell us what size it was," he said. "The factory people were very vague about that. They'd only say that it was bigger than 2. 5 liters, so speculation was it was about a 3.0-liter V-6."At 164 horsepower and 160 foot-pounds of torque, the engine can be expected to propel a moderately sized four-door over the road with considerable verve. Yet it's not one of those cars that will pass anything on the highway but a gas station.Mazda rates a model equipped with a four-speed automatic transmission at 19 miles per gallon city cycle and 25 mpg on the highway. If you want to do all the shifting yourself, the five-speed manual gearbox version delivers 21 mpg in the city and 27 mpg on the highway.For drivers looking for lower purchasing costs and optimum fuel economy, the smaller but less powerful four- cylinder-powered DX and LX models will be more appropriate.The 2.0- liter four-cylinder still produces a respectable 118 horsepower and 127 foot- pounds of torque. However, going down in size means going up ingasoline mileage. The 16-valver is good for 23 mpg in the city and 31 mpg on the highway. I n manual transmission form its 26 mpg in the city and 34 mpg on the highway.As long as the engineering department was building a new car, it went the whole route and revised the suspension to accommodate the lower hood line and lighter weight. Front struts were lowered to reduce hood and cowl height. While in the back, Mazda's Twin Trapezoidal Link suspension has been revised for improved ride and control.Resistance to bending has been improved 40 percent, and torsional rigidity has been increased by 20 percent.All three models offer a range of standard equipment. Even on the ES, leather is an option. An anti-lock brake system is available on all models.Mazda kept the price structure as well as most of the specifications under wraps."They told us they were going to try to stay as close as they could to holding the line," Gold said. "I'm going to guess about a 2 percent increase, but with that you're going to get some added features."Then there will be the cost of the bigger (V-6) engine. But with that bigger engine you'll get the speed-rated tires. You'll get more than just an engine."VThe current 626 with a fairly decent amount of equipment retails for $14,000 to $15,000. Dealers project the new one will be in that range, plus the cost of the V-6.In addition to the 626 sedan, Mazda will bring out a two-door MX-6 coupe that also will be built exclusively at Flat Rock. The car essentially is a coupe version of the sedan."They had them side by side," Gold said, "and the coupe was the same as the 626 except for the shell."