In the want ads they abbreviate the name to what a lot of people always thought their owners were -- Cad.

Cad is classified language for Cadillac. Nowadays there are two full columns of used Cads in the Sunday paper and the prices keep going down, down, down.

Henry, a neighbor who despises the family economy car and wants a Cad in the worst way, has it all worked out.

"Look, we all know there's only so much gas and it's gonna run out. We also know that when it does everybody is going to work like mad and invent some new way to run the country.

"But this conservation business has got to go. It just delays the inevitable, makes people pessimistic and keeps the scientists from going whole hog on new technology.

"It's obvious. The only truly American thing to do is use as much gas as you can and get it over with."

Henry was eyeing a 1970 Eldorado at the used car lot near the Takoma Metro station a few weeks ago. The price, plastered across the windshield with soap -- an incredible $311. For a Cadillac.

They couldn't sell it. Two weeks later the soapy figure dropped to $250 and finally it sold. Henry was crushed. He'd let another bargain get away.

"It's the American way," he said. "All the rich people are riding around in cars the size of roller skates. I say if you believe in America, get behind the wheel of a Cadillac."

That would suit one unhappy Cadillac owner in Potomac just fine. He bought his covertible new in 1970 and has maintained it with a loving hand.

He tried to sell it in 1973 during the first fuel crisis, but couldn't get a decent price.

"Now," he said, "I practically have to give it away. I only advertised it for $1,500 and I can't even get an offer."

"This car is perfect. New battery, rubber, brake linings, full power. But nobody is interested in buying it. I can't say I blame them."

The owner, who asked to remain anonymous, said fuel shortages and price alarm him and his prospective customers. His convertible gets eight to 10 miles per gallon and he worries about rationing and shortages of supply.

None of which worries Henry, who doesn't intend to drive the thing much anyway.

There are, of course, other reasons not to buy a Cadillac, Says one detractor: "It's the iridescent leisure suit of cars. It shows you don't care at all about conservation. It's disgusting."

Responds Henry: "People don't like them because they're not fashionable and that's all there is to it. If you drive an old Cadillac today you're a rebel, a real outsider. A hippie."

I manage to stay outside all this wrangling because my principal interest in Cadillac buying is spending my weekends inspecting old Cadillacs and marveling at what bargains they are. I'm too chicken to own one (what would mom say?), but I love test drives.

For example, from last week's paper: 1974 Sedan DeVille, four-door, air conditioning, power steering, power brakes, power windows, power seats. $1,075.

Or a '72 Fleetwood Brougham (the one Henry really wants), $950; or a '69 Fleetwood limousine, $850.

In Europe, a great premium is placed on aged quality possessions that have been cared for. In America, if it's three years old it's a heap looking for a junkpile.

Henry thinks it's a matter of national pride. If you're proud to be an American, he figures, then you ought to have a Caddy in the drive.

Even if you never turn the key.