Expanding on plans to make a variety of powerplants from a few highly flexible “modular” families (see story, p.1), General Motors Corp. confirms it will build all-new inline 4- and 5-cyl. engines at its new Flint Engine South plant in Flint, MI.

The new inlines will share about 75% of their parts with the Vortec 4200 straight-6, which went into production early this year for GM's all-new midsize sport/utility vehicles (SUVs). Although GM's Powertrain division officially says only that the new engines will be used in future trucks for the North American market, sources indicate they will debut in the upcoming Chevrolet S-10 compact pickup replacement, coded GMT355 and likely to be called Colorado. Sources also have said that there will be no GMC counterpart when the new Colorado is launched next year as an '03 model.

The inlines will share modern design features with the Vortec 4200, including dual overhead cams and electronically controlled throttle. An insider tells Ward's that unlike the Vortec 4200, the new engines will be fitted with twin balance shafts for smoother quieter operation, although “the 5-cyl. really doesn't need it.”

GM confirms it will produce a new version of its small-block Vortec V-8 employing “displacement on demand,” a system that shuts down four of the engine's eight cylinders when not needed. This V-8, slated for fullsize pickups and SUVs in 2004, will increase fuel efficiency as much as 25%. Eaton Corp. will supply the electromechanical system to enable selective deactivation of the cylinders.

GM brought a similar system to production — called the “V-8-6-4” — for Cadillac in 1981 to avoid the newly instituted gas-guzzler tax. Due to the lack of sufficiently sophisticated electronic controls, the V-8-6-4 did not perform well and lasted two model years.