GM's shorter, lighter luxury cars bring in big sales

The timing could not have been better. When mighty General Motors rolled out its truncated, top-luxury C-body cars in April, they fed into a fast-moving stream of prestigious cars that shows no hint of slowing down.

Clearly, Americans are in an up-market, car-buying mood with flush purses and a yen for the best.

From Jan. 1 through June 20, sales in the high-luxury auto market (GM says anything over $12,000 is a luxury car, but Ford Motor Company disagrees) - Cadillacs, Lincolns, Mercedes, BMWs, Volvos, Audi 5000s, etc. - were up 24 percent over the same period last year, compared with a 20 percent increase for the entire domestic and import car industry.

Specifically, Ford's Lincoln sales were up 57 percent, Cadillac 14 percent, Mercedes-Benz 19 percent, and BMW 47 percent.

Stocks are low on all of them, with Ford reporting a 35-day supply of Lincoln Town Cars and GM's Cadillac division 40 days. ''We have only a seven-day supply of front-drive Fleetwoods and De Villes,'' chirps a Cadillac Motor Division spokeswoman.

People ask why. ''We have a spreading social dichotomy in the United States, '' says L. R. Windecker, a Ford statistician. ''It isn't just that luxury cars are selling well,'' he adds, ''but there also is an increase in three-oven kitchens and backyard swimming pools.''

Thus, GM, in contrast to the US auto industry's disastrous timing on some new-car introductions in the past, is right on the mark with its upscale C-cars.

The new cars are some two feet shorter than the full-size, rear-drive, C-body cars which GM continues to sell. Too, the new-model cars are narrower and lower, while the wheelbase is 8 to 11 inches shorter. The Cadillac wheelbase drops from 121.5 inches to 110.8; the '85 Buick and Oldsmobile's 110.8 compares with 119 in '84. The new cars are also some 600 pounds lighter.

At the same time, however, the loss of cubic volume inside the cars is negligible, although from the rear seat the downsizing is more visible, particularly if the front seats are all the way back on their tracks. No matter, the top-flight Buick is still an Electra, the Cadillac Fleetwood and De Ville are still Caddies, and the best of the Oldsmobiles is still a 98.

Handling, pickup, and ride are right up to expectations, despite the downsizing. Workmanship also appears high, a major aim in GM's top-luxury-car programs. Originally, the C-body cars were due to be launched last fall, but the company's insistance on quality compelled GM to delay the entry till spring.

Despite all this effort, however, a faulty automatic door lock showed up on the Cadillac Fleetwood. A small matter to repair, I expect. In total, the cars are very well put together. Detroit is learning!

Cadillac still keeps its 4.1-liter V-8, although it is adapted to fit sideways under the hood. It took some redesigning of the water pump as well as a single accessory drive-belt system to save space.

Buick and Oldsmobile have V-6 engines, in contrast, and an optional 4.3-liter diesel as well. The diesel also is an option on the Cadillac De Ville. Cadillac uses a new 4-speed automatic transmission and exclusive viscous clutch to make shifting gears a dream. Cadillac also offers an extra-long warranty package with its new car.

The apparent success of its most-recent downsizing of the C-body car is in sharp contrast to the first downsizing in 1976 of the '77-model cars. Car buyers are obviously getting more accustomed to the idea that ''small'' doesn't need to mean ''less.'' But even so, some motorists still prefer a large car in the typical American fashion of long ago.

The new GM luxury cars are built in two of the most modern assembly plants in the world, Orion Township, Mich., and Wentzville, Mo. Both plants now build the Oldsmobile 98, while the Cadillacs are built in Michigan and the Buick Electra, T-Type, and Park Avenue in Missouri.

As for mileage, both the Cadillac V-8 and the Buick V-6 turned up less than 20 m.p.g. in a combination of city-type driving and suburban 35 to 50 m.p.h., but nothing on an Interstate. In an early-morning, light-traffic commute, the figure rose into the low 20s. On an expressway, with little up-and-down movement , the m.p.g. was inthe mid- to upper 20s.

The Buick Park Avenue is base-priced at $15,752, but with options the test vehicle ran up to $19,317. That latter figure wasn't even the base price of the Fleetwood. The top-of-the-line Cadillac carries a suggested retail price of $20, 402, $25,884 with options.