When Lenny Hale, the racing secretary at Belmont Park, assigned the weights for Saturday's Marlboro Cup, he was doing more than trying to give all the horses a theoretically equal chance. He was attempting to put those horses in the proper historical perspective.

The greatest horses carry the greatest weights. Forego's 137-pound assignment in the 1976 Marlboro Cup was as much a badge of honor as a burden. Last year, the good (but hardly sensational) California horse Perrault was asked to carry 128.

So when Hale put 124 pounds on Bates Motel and 119 on the 3-year-old Slew o' Gold for Saturday's Marlboro, he was saying he does not consider this to be a particularly distinguished group. His view was underscored by the fact that the two favorites are being asked to make only small weight concessions to Deputed Testamony, who has finished out of the money in his last two starts against 3-year-olds, and to Hyperborean, who has never done anything to suggest he is a top horse.

Hale's opinion coincides with the widespread notion that there aren't any exceptional racehorses in America this season. But he's wrong.

I have been writing repeatedly this fall that Bates Motel is one of the best American racehorses I have seen in years. Certainly his record at Santa Anita this winter, as well as his overpowering victory in the Monmouth Handicap, supported that opinion. But when he lost the Woodward Stakes by a nose to Slew o' Gold, many people concluded that he was just other one of those spurious, overrated West Coast horses, and that The Washington Post's turf writer had been exposed as an idiot for the umpteenth time.

In fact, the Woodward confirmed Bates Motel's excellence. It also suggested that there are two top-class horses in the land, instead of only one. Although Slew o' Gold had not previously done anything to suggest that he was a star, the time of his victory--1:46 3/5 for 1 1/8 miles--proved that he had suddenly become one.

Since New York's fall championship series began in 1973, I have been calculating speed figures that enable me to compare horses who race on different days and even in different years. Almost every top American horse of the last decade has run 1 1/8 miles at Belmont, either in the Woodward or the Marlboro Cup (which used to be contested at that route). If all of these horses had run over the track on which Bates Motel and Slew o' Gold competed, these would have been the best times, calculated in tenths of a second:

Secretariat (1973) 1:46.1

Spectacular Bid (1979) 1:46.2

Seattle Slew (1978) 1:46.3

SLEW O' GOLD (1983) 1:46.6

BATES MOTEL (1983) 1:46.6

Island Whirl (1982) 1:46.7

Riva Ridge (1973) 1:46.8

Affirmed (1978) 1:46.8

Pleasant Colony (1981) 1:46.9

Winter's Tale (1980) 1:46.9

That's pretty impressive company, and the performance of Slew o' Gold and Bates Motel relative to these acknowledged greats is even better that those numbers suggest. Some of the horses (Seattle Slew, Island Whirl) ran so fast because everything was in their favor; they were able to take an easy early lead with no pressure. Slew o' Gold and Bates Motel ran fast the hard way, swooping around the field on the turn, three- and four-wide, respectively.

For Bates Motel, my figures suggest, this was a typical performance. He runs fast all the time. For Slew o' Gold, it remains to be seen whether this was a single isolated, explosive performance, or whether he has belatedly developed into a horse who will now regularly run this well.

We will find out on Saturday. Many people (including Hale) may think this is a rather tame running of the Marlboro Cup, compared with the memorable years when Secretariat was facing Riva Ridge, or when Seattle Slew was challenging Affirmed. In fact, it may be another classic.