Washington Post Staff Writer

You might have seen the commercial: A businessman steps out of a country club and asks for his Lincoln Town Car. Another pinstriper leaving the place demands his Cadillac Brougham.

The executives exchange wary glances. The Lincoln fellow brags that his car is big. The Cadillac man sniffs: "Mine is bigger."

Got the picture? Okay, cut and rewrite.

The new scene is the White House, where President Reagan and Soviet General Secretary Mikhail Gorbachev have just signed the first treaty reducing the size of their nations' nuclear arsenals.

Gorbachev leaves first and asks for his limo, the ZIL 114 stretch job that's been tooling around Washington this week. Reagan follows, and orders up the White House ride, a super-stretched version of General Motors Corp.'s Cadillac limousine.

Imagine, now: The ZIL, with its powerful, 7.7-liter, V-8 engine pulls up. Gorbachev turns to Reagan and says something like: "Very big car, eh, Mr. President?" Reagan sniffs. The Cadillac rolls up. "Mine is bigger, comrade," says the president. "Mine is bigger."

Reagan would be right. The Moscow-made ZIL is big, all right. But the Detroit-spawned Cadillac is much bigger.

Look at the wheelbase, the centerline distance between the front and rear wheels. The ZIL, which has existed in its present form since 1977, has a wheelbase of 152.76 inches and an overall length of 248 inches, according to information culled from World Cars, published by the Automobile Club of Italy, and tips from other sources familiar with the vehicle.

"If I had to compare the ZIL with an American car, it'd be with a 1960s-style Lincoln limousine, which had a big 7.5-liter engine and the same kind of boxy body," said Wilfred O. Biehl, a Washington area expert on foreign cars.

The president's four-year-old Cadillac, one of two specially equipped Cadillacs made for the Reagan White House, has a wheelbase of 161.5 inches and an overall length of 261.3 inches, according to information released by GM and verified by the Secret Service.

The White House limo also has a bigger engine, an 8.2-liter V-8, versus the ZIL's 7.7-liter powerplant.

Which car is faster? It's hard to say for certain. The Secret Service has stuck a classified label on the White House limo's weight, turning radius, gas tank capacity, fuel efficiency and maximum speed.

But the ZIL? Well, it is a weighty thing at 6,802 pounds, and its massive, square face is an affront to aerodynamic efficiency. But those Russian wheels can move, up to 124 miles an hour, thanks to an engine that develops up to 316 horsepower at 4,600 revolutions per minute.

The ZIL's 10.8 miles-a-gallon fuel efficiency is not bad, considering its weight and engine. It carries a 31.7-gallon fuel tank.

But the ZIL has a mighty difficult time making sharp turns, mostly because of its gargantuan, 53.8-foot turning radius. The White House limo reportedly is much more maneuverable, according to sources who declined to give specifics.

Both the ZIL and the Reagan Cadillac seat seven -- five behind a partition in the passengers' section and two up front. And, of course, both are heavily armored. The "defense work" on the White House limo was done by Hess & Eisenhardt Armouring of Cincinnati.

Price? Forget it. That information was unavailable for either limo, but sources were certain that the costs are far out of the reach of most normal souls.

U.S. buyers desiring to own a White House-type limo should probably content themselves with a Cadillac Brougham sedan, which carries a 1988 base price of $23,846. For affluent Russians, there is the full-size Moskvich.

Ah, yes, the names. Nomenclature is a mystical art in the world car industry. But the Russians seem to have taken a practical approach with the ZIL. The name stands for Zavod (Factory) Imena (in the name of) Lenin, the founder of the Soviet state.

ZIL used to be ZIS, Zavod Imena Stalin, named for Lenin's successor. ZIL replaced ZIS in the 1960s, after Stalin fell from official favor.

GM named Cadillac after Antoine de la Mothe Cadillac, a French explorer who established the Ville d'Etroit ("village of the straits") in 1701. The Ville d'Etroit, of course, is now the City of Detroit.

The "Brougham" often found in the name of GM cars is just the manufacturer's way of saying that you will pay more for that model.