William P. Masselli gets up a 4 o'clock every morning to start work at his wholesale meat company in the south Bronx. The company is in a gray brick, windowless warehouse that was, for months, the target of electronic surveillance by the FBI. Masselli says the snooping doesn't even bother him any more.

"They can investigate all they want," he told a visitor the other day in response to allegations that he is a member of the Mafia. "It's ridiculous. . . . If I was in organized crime, you think I'd get up a 4 o'clock in the morning and work till 7 at night?"

The FBI, however, says its investigation is continuing. One focus of the inquiry is another business Masselli started some 4 1/2 years ago with a black state senator from the Bronx, Joseph L. Galiber.

It is called the Jopel Construction and Trucking Co., and it is listed on the books of the New York City Transit Authority as a qualified minority business enterprise.

Masselli, whose real first name is Pellegrino (the "Pel" of Jopel), is the president and treasurer of the corporation, but he says he owns only 49 percent of it. The other 51 percent is listed in the name of state Sen. Galiber, the "Jo" of Jopel and its vice president-secretary.

Not everyone at the south Bronx warehouse that serves as headquarters for Jopel as well as Pellegrino & Masselli Meats Inc. is aware of that.

"Billy [Masselli] is the top banana," one worker said. He paused a bit when asked about Galiber, then allowed that the state senator had "some connection" with Jopel that wasn't entirely clear to him.

Since its incorporation in November 1976, with an investment of $15,000, the company has grown into a multi-million-dollar-a-year business, primarily as a subcontractor on New York City subway projects for Secretary of Labor Raymond J. Donovan's company, Schiavone Construction, and several allied contractors.

The business ties were mentioned at Donovan's Senate confirmation hearings when FBI officials said their New York field office had developed information that Schiavone Construction, where Donovan had been executive vice president, was "mobbed up."

Donovan hotly denied the allegation, and FBI officials emphasized that they had not been able to corroborate it. They said the information came from three separate, usually reliable, sources, one of whom told them that Schiavone's ties to organized crime stemmed from its contacts with Jopel Construction and Masselli, "an alleged self-admitted 'soldier' in an organized crime group."

Masselli, 54, bristled indignantly at such talk as he inspected a copy of the hearing record, including an admission at one point from FBI executive assistant director Francis M. (Bud) Mullen that he did not bring along "any background whatsoever" on Masselli to support the description.

It's unreal. It's not fair," he said. "They know I'm a hard-working man. . . . I'm a legitimate person. As far as [my] being organized crime, forget it. My name ends in a vowel."

One reason the FBI might know of Masselli's work habits may lie in the fact that its agents tapped the telephone and reportedly planted several listening devices in Masselli's private office at one corner of the building for more than three months in 1979.

The records reflecting the surveillance, stuffed into half a dozen brown envelopes, "a large brown briefcase," and several other folders, are still sealed under court order at the federal courthouse in downtown Manhattan.

The surveillance was said to have produced more than 90 hours of taped conversations, replete with references to political influence and organized crime involvement in city and state construction projects, talk of truck hijackings, narcotics trafficking and the price of heroin and cocaine.

According to an account last year in The New York Times, the tapes also contained numerous comments concerning the shifting hierarchy of organized crime, and even produced some leads on an unsolved 1978 murder.

Asked about such reports, Masselli spread his arms expressively in one of the warehouse's red-tiled meatprocessing rooms and gestured with a cigar toward his office.

"I have four, five phones," he said. "Anyone who comes in here can use them. You come in here. Use the phone. Go ahead. I don't know who all uses the phones."

His glasses perched like goggles atop his forhead, Masselli broke into a broad grin when asked how he managed to turn Jopel Construction into such a success, making so much out of so little.

According to records submitted to the Transit Authority several years ago, the company was started with an initial down payment of $3,825 from Galiber and $3,675 from Masselli, half of the $15,000 they pledged.

With that, they took over a company that was going broke, assumed a reportedly troublesome excavation contract it had for a new subway station in Long Island City (Schiavone and another firm were the general contractors), and logged a gross income of $1.45 million in 1977, its first year of operation.

By now, Masselli estimated, Jopel has reached a volume of $3 million to $4 million a year. Its trucks are all over town, lining up each day on Manhattan's East Side to haul mud and rocks from the 63rd Street subway site, taking gooier muck out by way of Long Island City, dumping other materials from other jobs in Far Rockaway.

Its 63rd Street subway contract alone, as a minority subcontractor for Schiavone and two other joint venturers, has already produced more than $7.3 million for Jopel. Excavation is its forte, but the company still owns almost none of the trucks and other equipment that bear the Jopel label. Ninety-five percent of it is leased.

"There's no magic in it," Masselli said. "All it takes," he added with an earthy gesture below the belt, "is b----s, luck and a little business sense. That's all you need. And we got lucky. We did a rock [excavation] job on Vernon Boulevard. We found people need rock to build up the shoreline. We bid on another job to excavate 150,000 yards of sand. We knew where we could sell it."

And how did someone who had been "in the butcher business since I was 10" learn so much about construction work?

"I knew a little about construction through some friends of mine," Masselli said. "I palled around with people in the construction business."

One such acquaintance was Louis E. Nargi, who turned over the Long Island City subway excavation work to Masselli in 1976. Nargi said he wanted out because "the earth was bad -- it was a bad job" and "I had a lot of other stuff going." He said he thought of Masselli, an old friend from public school, because "he was always looking to go into other businesses."

Nargi expressed surprise on being told of Masselli's alleged ties to organized crime. FBI officials suspect him of being a member of the Genovese crime family. Nargi acknowledged that he had been aware of the FBI investigation and wiretapping back in 1979, but he insisted, "I thought they were after Mr. Galiber."

Sen. Galiber could not be reached for comment. A state legislator for 13 years, he had been tried, and acquitted, in 1978 of federal conspiracy, mail fraud and perjury charges involving an illegal real estate scheme financed by antipoverty funds.

As a Transit Authority examination in 1979 on Jopel's application for minority business status, officials were told that Gailber would be in charge of such matters as "corporate policy, government liaison, industry liaison, public relations" and the like.

Galiber told Transit Authority lawyers at the session that a minority firm simply needed to be one "controlled by one or more socially or economically disadvantaged individuals."

" . . . Because I'm black," he continued, "I think the fact that you're a minority, which I am, you have a social disadvantage."

Transit Authority officials say Jopel Construction is still a minority business in good standing as far as they are concerned. Federal mass transit officials say they are still reviewing an updated version of the Transit Authority program that failed to pass muster several months ago.

As for his dealings with Secretary Donovan in the past, Masselli reiterated what Donovan said at his confirmation hearings: that they had spoken to each other no more than three times over the years, about business matters.

Donovan has also been asked, briefly, by a reporter about other allegations of ties to the Genovese crime family. He replied:

"I can't even spell the word 'Genovese,' for Chrissake."