"My father told me never to bet on anything but Notre Dame and the Yankees," New Jersey Gov. Brendan Byrne said as he cut the orange ribbon at 10 a.m. yesterday. "For those of you not willing to take my father's advice, this casino is now open."

And within minutes, the casino floor was thick with more than 5,000 people happily disregarding the governor's father's words as legal casino gambling came to the East with the opening of the Resorts International Hotel Casino. Gamblers were standing in line to get in the casino, standing in line to buy silver dollars for the slot machines, and were taking every available space at the blackjack and craps tables.

Mary Anne Finney said she drove all night from Pittsburgh to be first in line at one of the casino entrances. She stood for two hours before the opening and then raced for a slot machine. On her third pull she hit a $300 jackpot.

"I broke the bank," she said laughing as she and her mother carted their 300 silver dollars away in paper coffee cups.

"Dweet" Menditto quickly won $60 at a dice table and placed it all on a 15-to-1 bet. "Do these dice know who they're shooting with?" Menditto, of Hackensack, N.J., shouted as he cradled the dice.

He invoked his first wife's name and rolled, but his hot string ended.

"My first wife was a pain in the a -- anyway," he muttered. "Oooh, that $900 would have been nice. I would have had some ammo. You got to have ammo."

Menditto said he would go home after one day if he lost and stay on if he was winning. "I'm supposed to be at work tommorow," he shrugged,"but if I'm winning, I'll phone in."

Menditto, who likes noise while he shoots dice, looked around at the other players at his table. "Come on, let's hear it. This is the most unenthusiastic group of dice players I've ever seen. Here, I've got a hernia, but I'm screaming like this."

I.G. (Jack) Davis wasn't screaming, but he was smiling. "You're not going to get this smile off for a long time," said Davies, who is president of Resorts International, which owns the hotel casino here.

Resorts chairman James Crosby said his company spent $50 million on the casino hotel and was losing $14,000 to $20,000 a day running the hotel without the casino. Crosby refused to say how much he expects the casino to make. "We can't tell you because we don't want anyone holding us up, he said to reporters.

Despite the capacity crowd from the opening bell, there were no traffic problems in the first hours of the casino gambling in any state other than Nevada. However, the Memorial Day weekend, which drew about 250,000 here each year before gambling had not yet fully begun. Some officials have said they fear 500,000 people may try to reach this island city over the weekend.

Crosby said he expected some high rollers to be on hand on the first day of gambling, but there were not many in evidence. Anyone wanting privacy or quiet for his gambling would have been overwhelmed in the crush of largely polyester-clad bettors.

"High-rollers," Crosby remarked, "don't like their names in the newspapers." In the opening hours they would have encountered a swarm of television cameras.

The only empty casino seats were at the baccarat tables, where the minimum bet is $20.

You can play craps or blackjack for $2, although almost all the tables have a $5 minimum.

Unlike Menditto and crap shooters, the politicians who turned out for a $20-a-head dinner and floor show on the eve of the casino opening often spoke in terms that made it hard to remember they were describing gambling.

State Sen. Steven Perskie of Atlantic City, who criss-crossed New Jersey organizing support for the referendum that legalized casino gambling here 18 months ago, said: "We will build in this city a monument of which we will all be proud for years to come."

The editorial in Atlantic City's morning newspaper, The Press, compared hearing recent talk of monorails and other devices to develop this resort to the thrill of wathching the first moon walk on television. In a phrase familiar to Redskins fans, The press declared: "The future is now."

Byrne repeatedly called Atlantic City "a family resort."

The only children in evidence were six first and second graders from the Massachusetts Avenue School brought to Resorts by their instructional aide, Patricia Logan because she said, "They'd never seen a ribbon cutting."

They still haven't since they were too young to be allowed into the casino. But, they got to shake a governor's hand.

It was impossible to tell how many in the opening crowd were like Tom Caruso of West Orange, N.J., who said, "I'm not really into gambling, but I came because, you know, it's something new," and how many will be casino regulars.

John J. Bondira of Metuchen,N.J., said he will be coming to Atlantic City about once a week to shoot craps.

Bondira, a retired Army ordinance colonel, said he's often been to Las Vegas and has also gambled in the Bahamas. He figures he'll take Wednesdays off from his insurance business to gamble.

"Where else can you make $40 that quick?" he said as the dice turned up, in his favor. After about an hour, Bondiro was even with the casino, he said.

Connie St. Angelo wore a T-shirt with silver letters "Casino Lady," for opening day. "I lost $10 playing the slots, but I'll make it back tonight at blackjack," she predicted with a grin, "It's just wonderful," said her friend Millie Totoro, a waitress for 45 years in Atlantic City.

Anumber of the dice players complained that the action was too slow because the young croupiers on their first day handling real money were taking too long paying winning bets and collecting losing ones.

"I've got time to go out to the bathroom," Menditto complained as he waited to be allowed to roll the dice again. "You'd have to be here all day to make a good string of rolls." But Menditto predicted that the croupiers would get up to Las Vegas speed within a couple of weeks and none of the players was letting the delays drive them away from the tables.

"Yeah, hot roller," one bettor yelled when a point was made. "Throw them all night."

In the dimly-lit, crowded casino, it was still only 11:10 in the morning.