FIGURE 1 The 200 HP high performance 4.3L Vortec V6 engine has been developed to satisfy the need for a fuel efficient performance powerplant in the General Motors small truck platforms. Marketing requirements included strong low and mid range torque, relatively high specific power, smoothness and noise comparable to the best competitive six cylinder engines, excellent driveability, and a new technology image. Maintaining the 4.3L engine record of high reliability and customer satisfaction was an absolute requirement. Fuel economy and exhaust emission performance had to meet expected customer and legislated requirements in the mid 1990's.New engine features include: Dual tuned intake manifold with integral throttle body AC Rochester central port fuel injection High flow swirl port cylinder heads High lift roller camshaft Primary balance shaft AC Rochester linear EGR High alloy aluminum pistons An engineering product development team used the GM engine simulation program and “breadboard” development induction systems on test engines to evaluate alternative induction system proposals. A long runner design with controlled variable tuning was found to be the optimum configuration to meet engine performance requirements. AC Rochester was the tier one supplier and design responsible for the final intake manifold concept, fuel system, and EGR valve. This engine is the rollout application for central port fuel injection (CPI), linear EGR, and the electric motor driven intake manifold tuning control valve.Design, development, and validation of the as-installed engine package was done in cooperation with GM Truck and Bus and AC Rochester. The project was conducted within the guidelines of the GM 4-Phase Process. Initial applications are in the General Motors compact pickups, sport utility trucks, and mid-size vans.