There are two outstanding 3-year-olds with the initials S.S. in the United States this season. One is Seattle Slew the Triple Crown winner. The other is Silver Series, a gray colt ready to concede eight to 14 pounds to six or $100,000 Monmouth Invitational Handicap.

Silver Series is based in the Midwest. "That helps to explain his lack of national recognition considering his record," trainer Oscar Dishman suggested. "Most Easter people look down on horses from my part of the country. Why, I wouldn't be surprised if they made Iron Constitution or Affiliate favored over my horse tomorrow."

No chance. No such regional discrimination will surface at the betting windows. Silver Series has won his stakes defeating along the way such name 3-year-olds as Run Dusty Run and Cormoratn. Seattle Slew made his reputation by beating the same animals in the Triple Crown races.

Silver Series has captured the Hawthorne Derby, the Ohio Deby and the American Handicap in the last two months. NOt once was he favored that distinction going to Affiliate Cormorant and Run Dusty Run in those events.

So, perhaps, Dishman is justified for believing the racing and betting world does show a little prejudice against his horse. The trainer and the colt's owner, Archie Donaldson who are black, are in a white world when it comes to competing in top-class contests for thoroughbreds.

Black people have yet to make any major headway in this sport. Successful black jockeys belong to the turn of the cetury. Black track officials are one in number, nationally. The only black man I ever saw bidding on a yearling at Keeneland or Saratoga was Dick Allen, the baseball player. Black trainers are extremely few and far between. Black owners of consequence are even more difficult to find.

Economics is the key to the situation of course. It required considerable wealth to race or breed the better thoroughbreds.But there is more to the problem than that. Thoroughbred racing, on the highest levels, still is stuck with the Jockey Club stigman. When a Jew was elected to the Jockey Club a few years ago, it was news.

"Heaven knows I've been discriminated against during my 16 years as a trainer," Dishman said, "but I'm not saying it was because of my color. The people in charge of allotting stables simply didn't recognize the quality of my horses.

"My problem," Dishman added, "is to get more black people who have the money interested in racing; to get them to the sale. That's what I've been working on. Those that have the dollars must be shown it can be profitable for them to jump in. They must realize that racing is a good tax writeoff for their business.

"Unfortunately, some of the first blacks who started to invest in racing stables were stung pretty good . . . and they passed the word."

Dishman believes a black man has equal opportunity in the backstretch.

"There are some with the experience who don't want the responsibility of being a head trainer," he said. "They would rather stay as the top assistant to an established man. Sure I know it's hard for a black man to find horses to train. But it's hard for white man, too."

Donaldson, the owner, is a gynecologist from Nassau in the Bahamas. He met Dishman and got into racing while still an intern at a Cincinnati hospital. Dishman was training at nearby River Downs.

The owner and trainer enjoyed considerable success with Golden Don, an excellent grass runner during the early '70s. Now they are back with an even better prospect, bred by Donaldson. One which would appear capable of challenging Seattle Slew, Forego and J. O. Tobin for the Horse of the Year title this fall.

Nearly On Time, Pruneplum, Wilderness Bay, Tiny Monk and Don Sabastian complete the field for the Invitational, run over a mile and an eighth. Nearly On Time also is entered in the Whitney Handicap at Saratoga Saturday, against Forego.

Nearly On Time will be particularly strong threat in either race.