The 550-hp Shelby GT500 also loses something from the previous model--it's gas-guzzler tax. Ford says the new Shelby GT500 will deliver 23 mpg on the highway and 15 mpg in the city. The engine is rated at 550 hp and 510 lb-ft of torque.

Ford released details on the new Shelby GT500 on Monday. The car will be sold in coupe and convertible body styles, going on sale this spring as part of the full 2011 Mustang line.

The use of aluminum for the block helps cut 102 pounds from the engine. Instead of cast-iron cylinder liners, Ford uses a process named Plasma Transferred Wire Arc to spray a thin coating of iron on the inside of the cylinder bores. The process, adapted from the aerospace industry, saves eight pounds compared with a traditional aluminum block with iron liners, Ford says.

For those seeking even better handling performance, an available SVT Performance Package adds lighter wheels, a higher rear-axle ratio, stiffer springs and unique high-performance Goodyear tires.

Other changes include electric power steering and high-intensity discharge headlamps as standard equipment, and an optional glass roof for the coupes. All Shelby GT500s will continue to be fitted with Ford's stability-control system.