But the GM engine has higher torque, competitive fuel economy -- 18 city/24 highway, up from 15/20 from the old V-6 -- and such advanced technology as direct fuel injection, variable valve timing and cylinder deactivation. The comparison is of V-6s with the best fuel economy available in the three pickups.
GM spent $400 million to revamp the Tonawanda plant to build the V-6 and three redesigned V-8s. The engines belong to the fifth generation of Chevrolet's small-block family. All the engines are assembled on the same production line -- the first time GM has assembled V-6s and V-8s on the same line.
The 5.3-liter V-8 is used in pickups. Two versions of the 6.2-liter V-8 are produced, one for trucks, the other for the Chevrolet Corvette Stingray.
The Tonawanda plant, which was opened in 1938 and is one of GM's oldest, is now one of its most advanced. Giant robots lift unmachined cast engine blocks and place them in cells where the bores are honed, cam bearings are pressed in and bolt holes are threaded.
A machine installs all the intake and exhaust valve components in about 40 seconds. Before an engine is released, another set of machines measures the surfaces of the block and cylinder heads for imperfections. More than 11,000 checks of each engine are made, GM says.
Plant manager Steve Finch says GM can produce 1,600 engines per day on three shifts. Production is expected to be 70 percent V-8s and 30 percent V-6s.
Jordan Lee, chief engineer for small-block engines, said the new 4.3-liter V-6 was designed to be a truck engine and is not a converted car engine. "We looked at smaller and larger displacements, but the 4.3 gave the torque curve we wanted for a V-6 pickup," he said.
Lee said the plant's new manufacturing flexibility can accommodate future small-block engines with other displacements.