There's a lot of new automotive styling for 1988 -- cars and trucks with sleeker and more stunning bodies. But the real changes are mostly underhood and underbody, well out of the sight of new-car buyers.

For example, there is General Motors Corp.'s new optional Quad-4 engine, a four-cylinder engine with four valves per cylinder that produces as much horsepower, or pulling power, as some V-8 models.

Engines essentially are air pumps. They take in air, mix it with fuel, compress the mixture, burn it and expel the waste gases, producing usable power.

Engines that can handle large volumes of air and exhaust gases efficiently are more powerful than those that can't.

Most auto engines have two valves per cylinder -- one valve to let air in and another to release residual fumes. Increasing the number of valves per cylinder raises the efficiency of compression-combustion-exhaust operations.

GM's Quad-4 is not the first 16-valve model -- the Japanese and Germans have been selling them in the United States for several years.

But the GM model, which uses computer controls, does advance the art.

Other items include four-wheel steering, introduced on some 1988 Honda, Mazda and Nissan models.

The object here is to increase vehicle maneuverability by allowing all wheels to turn in the same direction in high-speed driving -- changing lanes on an interstate, for example. In low-speed situations, such as parallel parking, four-wheel steering turns the front and rear wheels in opposite directions, allowing the vehicle to slip into relatively tight spots.

Antilock braking systems also will be prominent on 1988 models, particularly on domestic and import luxury cars and on full-size pickup trucks made by Ford Motor Co. and GM.

The mechanism electronically pumps the brakes of a vehicle in panic situations, helping the driver to reduce speed without locking the wheels, losing traction and, eventually, losing control of the vehicle.

Other safety items are visible. They include air-bag pouches in steering wheels. The air bags are designed to "explode" within milliseconds of a collision, providing a face-saving and often life-saving cushion for the driver.

Also, shoulder-harness seatbelts for rear passengers will be on many 1988 models, as well as front-seatbelt and shoulder pillar anchors that can be adjusted up or down.

The adjustable anchors are a good item for people who complain that standard seatbelts and shoulder harnesses fit uncomfortably across the neck or too tightly across chests.

Auto entertainment centers continue to improve. Compact disc players are being added to auto stereo systems that usually feature radios and cassette players, for example.

The compact discs usually will be sold as options in more expensive cars.

Also, "driver information" items, such as electronic compasses, continue to grow in popularity. GM's 1988 Pontiac Grand Prix, for example, employs a video display compass that shows the exact direction of the car's front-end at all times.