Their objective was to improve smoothness and performance without sacrificing reliability, giving Chevy truck owners "the best of both worlds." And they succeeded.

"The challenge was to deliver in all areas -- not one or two at the expense of the others," said Volker Harhaus, GM Powertrain's Chief Engineer for Truck Engine Controls. The new Vortec 5700 V8 offers 25 percent more horsepower than its predecessor, delivering a performance improvement when towing or passing that Chevy truck buyers can really feel. Compare the increased power and torque available in the new standard engine to last year's models (C/K Pickup under 8600 lbs. GVWR):

	Horsepower	Torque (lb.-ft.)
1995 5.7 Liter	200 @ 4000 rpm	310 @ 2400 rpm
1996 5700	255 @ 4600 rpm	330 @ 2800 rpm
	+55	+20

Noise reduction was a high priority to increase customer satisfaction. Several refinements reduce noise and vibration:

The new Vortec 5700 V8 engine relies on advanced technology to achieve a high level of performance:

Sequential Fuel Injection (SFI) is available for the first time on a V8 engine. This GM-patented system provides the benefits of precise fuel delivery to each cylinder without the cost and complexity of conventional Multi-Port Fuel Injection.

The centerpiece of the SFI system is a single disk injector that is connected to eight individual poppet valves with flexible lines. The central injector controls the flow of pressurized fuel to the poppet valve nozzle in each intake runner.

The sophisticated yet simple SFI system delivers significant benefits to Chevrolet customers:

A mass airflow meter constantly measures the engine's air requirements under varying operating conditions, such as changes in load, altitude and temperature. By providing accurate information on the engine's air intake to the Vehicle Control Module (VCM), the mass airflow meter contributes to the small block's efficiency and performance.

Straight-port cylinder heads with revised combustion chambers improve airflow and raise the compression ratio to 9.4:1 (from 9.1:1 for 1995). This boost in compression ratio improves thermal efficiency and performance, but does not increase the engine's octane requirement.

The secret of the more powerful Vortec 5700 V8 is the new two-piece intake manifold design for optimum engine breathing. The distinctive black-and-silver manifold assembly consists of an aluminum lower half and a composite upper half. The composite upper manifold reduces mass and noise, acts as a thermal insulator and tunes the induction system for optimal airflow. The Vortec V8 is the first application of a composite upper intake manifold on a truck engine.

Roller lifters reduce internal engine friction and wear. An aggressive new hydraulic roller camshaft profile works with the revised cylinder heads to improve engine power. A steel camshaft replaces the previous cast-iron cam to withstand the higher contact stresses associated with roller lifters and give longer life.

The switch to a steel cam and roller lifters gave GM engineers the freedom to design fast-action cam lobes. The area under the valve curve was increased to augment power, yet a good idle quality was maintained. It's a win-win situation: more power, a stable idle, low hydrocarbon emissions and exceptional fuel economy.

The Vortec V8's roller lifter camshaft improves low-end torque for towing and trailering, while also extending the engine's dynamic operating range for faster acceleration and quicker passing.

The Vortec V8's cooling system has been improved for 1996. A controlled bypass thermostat improves bank-to-bank coolant flow balance, expedites warmup, enhances heater performance, and improves cooling by directing all coolant flow through the radiator when the engine is at operating temperature.

A crankshaft position sensor signals the Vehicle Control Module (VCM) to ensure accurate fuel delivery and spark timing for each cylinder. The crankshaft position sensor also aids in the detection of misfires and ensures that the engine is running at peak efficiency.

"Our goal for the '96 truck program was to make the powertrains maintenance free," said Volker Harhaus, Chief Engineer of Truck Engine Controls for the GM Powertrain Group. "And you can see from our new service intervals, we're getting close to achieving that goal." Extended maintenance schedules help make Chevy trucks more environment-friendly. Fewer parts to change and longer intervals between scheduled services mean less waste is generated.

The Vortec 5700 V8 is equipped with an enhanced exhaust system.

This advanced EGR valve offers much finer flow control than a conventional vacuum-operated valve, regardless of manifold pressure or engine load.

On-Board Diagnostics reach a new level of sophistication with the implementation of OBD II (On-Board Diagnostics Second Generation). A more powerful Vehicle Control Module (VCM) monitors the emissions system and its components to detect deterioration or malfunction.

Vortec 5700 V8s have new Revised Permanent Mold (RPM) pistons designed using sophisti-cated GM computer programs. Precision machining simplifies the manufacturing process by allowing a single piston size to be used in all engines.

The enhanced Vortec V8s are examples of the Chevrolet commitment to continuous improvement of its products. The application of advanced technology and innovative ideas has made the proven small block V8 a standout performer in the highly competitive truck market. With more power and quieter operation, the new Vortec V8s will add to the small block's longstanding reputation for excellence.