Sorting the nomenclature of GM's midsize cars

Built on the X-car floorpan with a 104.9-inch wheelbase, GM's front-drive A-cars--Chevrolet Celebrity, Buick Century, Pontiac 6000, and Oldsmobile Ciera--are the size and shape of the future in family transportation.

The new A-body cars do not replace the regular midsize rear-drive cars, however--Malibu, Regal, LeMans, and Cutlass. Rather, they supplement them and give the motorist an option: front-drive or rear-drive in close to the same size of car inside.

What it does, however, is complicate the GM scoreboard for the motorist.

Suppose you plan to buy an Oldsmobile Cutlass Ciera Brougham. Will you get a rear-drive or front-drive car? The answer is front drive. Remember, the Cutlass Ciera has the drive wheels in the front. But there's also a Cutlass with the drive wheels in the rear.

No wonder the slow-buying motorist is confused by the nomenclature.

Nonetheless, the fresh-looking General Motors A-cars are a large forward leap in engineering and overall quality control.

Each new car line should be better than the one it succeeds, GM reminds us over and over again. The point is, the corporation says it is advancing up the learning curve and that the new-era cars get better all the time.

Even so, more than a half million 1982-model cars now are caught up in a recall program to fix a problem which, GM says, could lead to a fuel leak. The recall involves not only the A-cars, but also the X- and J-cars as well.

The new front-drive A-cars are a foot longer than the three-year-old X-cars even though the wheelbase is the same.

The Chevrolet Celebrity is five inches shorter than the rear-drive Malibu, 3. 5 inches narrower, 2 inches lower, and a quarter of a ton lighter in weight, yet it shares many of the inside dimensions with the Malibu. It shows the advances made by the designers in bringing the automobile up to date with the times.

All the A-car bodies are lean, uncluttered, and clean.

In execution, the wedge-shaped Pontiac 6000 is closest to an import; in other words, the most European of them all. With flush windshield and side glass, the Pontiac 6000 smacks of a West German design staff.

Base engine is a Chevrolet-built 2.5-liter ''4'' with a 2.8-liter V-6 as an option in the Celebrity and a 3-liter V-6 in the others. A V-6 diesel also is available.

Options are legion in the A-body cars. As expected, this pushes the price into the sky. A well-equipped A-car, for example, costs upward of $12,000 even though it may carry a ''base'' sticker of $8,500 or less. The A-cars, like many other automobiles these days, carry a large rebate.

Indeed, options do cost money as consumers discover when they tote up the bill. And then there's that ''destination charge'' of $400 or so.

Detroit carmakers are painfully aware of the price squeeze, which is reflected in the rebates of many sizes and duration. Detroit's pricing policies on the array of new front-drive automobiles, in fact, have contributed to the snail's pace in sales.

Driving an A-car is a pleasant motoring experience that gets better all the time. Visibility is high and so is the head room. While the 2.5-liter ''4'' may be adequate for some drivers, a V-6 gives the power that many motorists really want in an automobile.

Besides the price, there are always some things that annoy in any car. In the Chevrolet Celebrity I suggest it's the horn. If you need the horn in a hurry, you may get by the crisis point before finding the horn on the wheel. The horn buttons are much too small and remote to be quickly used in an emergency. The Pontiac 6000 doesn't suffer from this design blooper, however.

Even though the A-cars are an offshoot of the X-cars, the three-year-old X-cars have a sportier, harder suspension to support the image of the ''X'' while the A-body vehicles are more ''American traditional'' in ride. The Pontiac suspension is somewhat more firm than the others in keeping with the its European-motivated image.

While the A's come only as 4-door sedans and 2-door coupes, a wagon is due down the road as well as a 4-speed manual transmission, now sold only in Canada. A 3-speed automatic transmission is used in the US.

There's little doubt that GM's new A-cars are a major departure from the canned Detroit market response of the past. Given a sales market even marginally better than today, they should do all right.

But don't expect them to push the imports off the road.

They won't.