Caveat made a powerful rally in the 1 1/4-mile Kentucky Derby, coming from 20 lengths behind to finish third. So he should perform even better in the 1 1/2-mile Belmont Stakes. Right?

High Honors finished like a whirlwind in the Preakness, passing eight horses in the last half mile. Classically bred, he figures to be a natural at the Belmont distance. Right?

Wrong in both cases.

Even though Caveat and High Honors are two -- of the top three choices in the morning line, history suggests that their credentials are not nearly as strong as they seem. Caveat's chances of winning are grossly overrated. High Honors' chances of winning are virtually nil.

Neither of these stretch-runners is the type of horse that usually wins the Belmont. The member of the record 15-horse field who fits the mold is Slew O'Gold.

Just about every year, a horse makes a big stretch run at Churchill Downs, as Caveat did; most of the time, these late moves are illusory. Because all of the horses in the Derby are racing farther than 1 1/8 miles for the first time, many of them are collapsing in that crucial final furlong. Some plodder in the field will usually pick up enough of the pieces to finish second, third or fourth, and when he does, thousands of bettors will exclaim in unison, "That's my Belmont horse!"

Remember Woodchopper's big rally in the 1981 Derby? Or Rumbo's in 1980? Or Prince Thou Art's in 1975? They were all bet heavily in the Belmont, and they all finished out of the money.

There is another, more legitimate type of horse that traditionally doesn't fare well in the Belmont, either--the type that seizes command of a race with a swift, sudden move, like Pleasant Colony or Spectacular Bid. It takes more than one move to win at 1 1/2 miles.

Horses who win the last leg of the Triple Crown series are usually even-paced runners, endowed with a fair amount of speed. Front-runners have captured six of the last 12 runnings of the Belmont, and only once during that period has a horse come from 10 lengths behind to win.

Without the assumption that they are especially well-suited to the Belmont, Caveat and High Honors come into Saturday's race with unimposing records. Caveat has won only two minor stakes in his life; High Honors has won none. Between them, they have lost 22 of their 29 career starts. Certainly, they don't have the credentials of either Deputed Testamony or Slew O'Gold.

Deputed Testamony was the beneficiary of very favorable racing luck when he scored his upset in the Preakness. And he has the running style--the swift move on the turn--that may not be best suited to the Belmont. But he is a good, tough racehorse, who deserves a lot more attention and respect than New Yorkers have been giving him this week. He will almost certainly be the greatest bargain on the tote board Saturday.

But the horse to beat is Slew O'Gold.

My old mentor, Steve Davidowitz, author of the handicapping text, "Betting Thoroughbreds," has been watching Slew O'Gold all spring and telling me that this colt is going to be the 3-year-old champion of 1983.

"His physical size was such that he was going to need time to grow and get stronger," Davidowitz said. "But even with that size he was a real athlete, and with every race he gave a more complete kind of performance."

I didn't share this enthusiasm for the colt, but when Slew O'Gold won his last start, the Peter Pan Stakes, by 12 lengths, it finally became obvious that he did have the ability to be a truly top racehorse.

That performance, followed by his :58-flat five-furlong workout Wednesday, showed that he is coming into this race in razor-sharp condition. The son of a Belmont winner, out of a mare who produced a Belmont winner, he is clearly bred for 1 1/2 miles. And he has the right running style.

In a field with relatively little speed, he should stay close to the leaders, run at a fairly even pace and further discredit the myth that stretch runners are supposed to win the Belmont Stakes.