* Fifth-generation GM small-block V8 debuts
* Upcoming 2014 Corvette will be 7th generation
* Corvette fuel economy to be slightly better than current 26 mpg
PONTIAC, Michigan, Oct 24 (Reuters) - General Motors Co said the redesigned 2014 Chevrolet Corvette that goes on sale next year will get a new 450-horsepower V8 engine. The engine, designated LT1, displaces 6.2 liters and is the fifth generation of GM's ``small block'' V8 engine family. Versions of the LT1 are expected to be used in other GM products, GM sources said, including the automaker' s redesigned 2014 Chevrolet Silverado and GMC Sierra pickup trucks. In the new Corvette, the LT1 will enable the sports car to accelerate from zero to 60 miles per hour in just under 4 seconds, or a few tenths of a seconds faster than the current model, said Tadge Juechter, executive chief engineer for Corvette. The LT1 will be ``the most fuel-efficient 450-horsepower engine on the market,'' GM said at a media briefing Wednesday at its global powertrain headquarters in Pontiac, near Detroit. This is the fifth generation of GM's small block engine, which was introduced in 1955. The 2014 Corvette will be the seventh generation of the iconic American sports car introduced in 1953. The engine press briefing was the first time GM has revealed specific details about the 2014 Corvette, other than the new logo which was unveiled last week. Jordan Lee, chief engineer for the small-block V8 program, said that the new Corvette will improve on the current model's combined highway-city fuel economy rating of 26 miles per gallon, but that the actual EPA rating will not be determined until closer to the car's launch at mid-year. Juechter said that there has been a lot of concern among the devoted legion of Corvette fans whether the 2014 model will remain true to the car's rich history. ``We are not going to be a shadow of our former self,'' said Juechter. The Corvette's sales are relatively low -- 10,570 through September, according to Autodata -- but it is ``truly an American icon'' largely because it is ``a relatively affordable sports car with great performance,'' said David E. Cole, a longtime auto industry expert and now chairman of AutoHarvest Foundation. Cole's father was chief engineer at Chevrolet when the original Corvette was introduced. The Corvette's engine will have direct fuel injection -- the first time GM has used it in an overhead-valve engine -- and active fuel management, a fuel-saving system that shuts off half the cylinders when the load on the machine is light. GM has employed the cylinder-cutoff technology in other models, but this will be the first time it will be used in a Corvette, said Lee. Juechter said the engine's designers heard from Corvette fans who were afraid GM would switch to a twin-turbo V6 instead of a V8. ``They have had a V8 for 57 years. They want their V8,'' said Juechter. He said engineers had considered such a switch, but in the end decided that the V8 was best for the car's performance. The 450-horsepower figure is preliminary, and its production figure will be determined early next year, said John Rydzewski, a lead engineer on the small-block engine program. The Corvette's engine will have peak torque of 450 foot-pounds at 4000 revolutions per minute, Rydzewski said. The new Corvette engine will be made at GM's Tonawanda Engine Plant in Tonawanda, New York, where the original 1955 small-block V8 was built. The current Corvette engine is made in St. Catherine's, Ontario. The Tonawanda plant recently underwent a $400-million upgrade, which will allow for production of the LT1 engine for the Corvette and other GM models that now have a V8, GM sources said. Another concern expressed Wednesday by journalists, which included many from car enthusiast publications, was whether the new Corvette would sound powerful. Not to worry, said Juechter. ``You can look forward to another generation of ground-pounding American thunder, '' he said.