The flashiest and most crowded party at the convention of auto dealers here this week was not put on by any of the four major U.S. automakers.

It was the DeLorean Motor Company's open reception to introduce John Z. DeLorean's new, innovative sports car, the DMC-12. The company also hoped to convince the industry that the former general manager of Chevrolet is not only serious about his new company but nearly ready to start production on his $15,000 car.

Almost everyone who dropped by left a believer, convinced that DeLorean will be the first man in a long time to start his own auto company successfully. Many others before him have failed.

There are good reasons for DeLorean's likely success. With the help of the Irish government -- his plant will be in Dunmurry, a suburb of Belfast -- DeLorean has put together a financing package estimated at some $140 million, startling success for a man with little knowledge of fund raising, and a far cry from the $7 million raised for the ill-fated Bricklin.

"When you work for General Motors and want to build a new foundry," he once said, "and you need$600 million, you fill out a form and send it away. You might get a phone call or two, or you might not. Then within a few months this document comes back with 100 signatures on it that says go spend the $600 million. Unfortunately, that's all I knew about raising money."

But he learned fast. First, he went to existing car dealers, many of whom knew and liked him from his GM days, and said he would let them have DMC dealerships only if they kicked in $25,000 for a piece of the company and agreed to take up to 150 cars.

To date, more than 225 dealers have signed up, kicking in about $5.7 million. And this week it looks like he will pick up several more.

In addition, DeLorean has put $4 million of his own into the company, raised more than $5 million at $5 per share in an early stock offering, and another $1 million from two large investors: one is a Canadian investment bank; the other is Johnny Carson, who will also give the first public pitch for the sleek sports car.

In late 1977, DeLorean asked Oppenheimer & Co., an investment banking firm that specializes in raising money for new ventures, to put together an investment package designed to raise up to$20 million for a limited partnership in the company by July of last year.

Oppenheimer did the job, getting 134 investors, including several Oppenheimer principals, to kick in at a minimum of $150,000 each.Another $18.8 million was raised.

But the big boost came last summer when -- after DeLorean had flirted with Puerto Rico as a spot for his plant -- Northern Ireland and the British government provided enough additional funding (estimated to be about $100 million) to put DeLorean over the top. He built his plant in Ireland.

"I expect the assembly plant to be completed by December, and the fabrication plant on the same site to be operating by April, 1980," the 54-year-old DeLorean said in an interview at his convention hospitality suite.

"We will be selling cars at the end of this year," he said. He said he is also planning to have all his employes -- including 2,000 plant workers -- own a piece of the company, because it gives them added incentives to help the company succeed.

DeLorean, who had the reputation as a high-powered GM executive with a strong engineering background, said the car he has built is the culmination of a long-standing dream he has had.

"I've had the concept for a long time," he said, "but never could get it produced commercially."

"It's a specialty car with a limited market," he said, "and Detroit just isn't geared to handle that kind of car." He said the car will be marketed "somewhere between the Datzun Z-model and the Porsche, about $1,500 over the price of a Corvette." DeLorean said he hopes to sell about 30,000 cars a year at full production, which he hopes to achieve within a year of opening.

The car has a highly unusual look, with a brushed stainless steel body coating (covering a plastic-foam composite) and the look of an Italian sports car -- it was designed by an Italian.

And, he says, it will be an "ethical" -- for lack of a better word -- car." That means it will meet nearly all federal safety, emission-control and fuel control and fuel economy standards not scheduled to take effect until 1985.

"You can crash in this car at 80 miles per hour and live," DeLorean says, although he won't speculate on the condition of an occupant after such a crash.

That aspect of the car interests federal regulators. National Highway Traffic Safety Administrator Joan Claybrook calls DeLorean "fascinating," and says it is likely he will work with the government to help it develop safer cars.

"We are already developing what the government is studying," DeLorean says, but adds that he, too, is anxious to work with the regulators, particularly on some new models, including a sedan, he has on the drawing boards.

"If anybody can do it, he can," said Johnny Carson about his new partner. "I've known him for years, and he knows this business as well as anyone. I think this car is going to make it because it has an appeal to many people -- it's not just a kid's car."

Carson doubtlessly will make an effective pitchman as well. Walking into DeLorean's reception, Carson was approached by a friend who pointed to the car, turning on a pedestal in the middle of the room, and asked, "Is that the car?"