General Motors is investing close to $332 million at four of its manufacturing sites in order to build new, more fuel-efficient powertrains. These new powertrains include a new V-6 engine, an eight-speed transmission, and tooling for an existing six-speed transmission. The GM plants receiving this investment are in Flint and Bay City, Mich.; Toledo, Ohio, and Bedford, Ind.

The automaker is also investing $46 million more (bringing the total to $646 million) in its powertrain plants in Romulus and Saginaw, Mich., to support production of the new V-6 engine. According to GM, these combined investments will retain roughly 1,650 jobs at the six facilities.

At the Flint Engine Operations plant, $215 million is going to production of a new small Ecotec gasoline engine, which is part of a new engine family that includes 3- and 4-cylinder variants with displacements ranging from 1.0 to 1.5 liters. GM said it will provide details on the variants the plant will build at a later date. The plant is also upgrading its tooling for the current version of the V-6 it produces.

At the Toledo Transmission Operations plant, GM is investing $55.7 million to increase capacity and tooling to build an all-new eight-speed automatic transmission and for an existing six-speed. GM said the all-new eight-speed will be used in a number of GM vehicles by the end of 2016.

Next, the automaker is investing $31.7 million in its Bay City Powertrain plant, including $19.2 million to produce components for a new V-6 engine and $12.5 million for the small Ecotec gasoline engine mentioned previously.

Lastly, the automaker is investing $29.4 million in the Bedford Castings plant, including $19 million to build components for the small gas engine and $10.4 million to produce components for the new eight-speed and existing six-speed transmissions.

For the $46 million at the Saginaw plant, the automaker is spending $41 million to build castings for the new V-6, and at the Romulus Engine Operations plant, GM is spending $5 million for the new V-6 engines.