Actor Jack Klugman probably doesn't need any windfalls, but he got one anyway this week.

He picked up his phone Thursday afternoon to learn that his colt, Jaklin Klugman, was the favorite to win a $300,000 race that he had not even been expected to enter.

Trainer LeRoy Jolley judiciously planned to keep the 3-year-old on the sidelines while invincible Spectacular Bid ran in Saturday's Marlboro Cup. sBut when Bid's trainer, Bud Delp, chose to duck his 136-pound weight assignment, Jolley altered his plans instantly. And because there is such a shortage of high-class horses in the country this year, Jaklin Klugman became the justified 5-to-2 morning-line favorite in the country's most prestigious handicap race.

Casual racing fans who last remembered her seeing the colt trounced by 15 lengths in the Preakness may be surprised by his current lofty status. But just like show biz, racing is a game in which reputations can be made overnight.

Jaklin Klugman has been suffering from foot troubles this spring, and after the Preakness he got a much-needed rest. But the principal cause of his transformation was probably his owner's decision to take him from his little-known West Coast trainer, Riley Cofer, and send him to Jolley in New York.

Under Jolley's tutelage, his improvement has been stunning. Jaklin Klugman made his return to competition by scoring a seven-length victory in a minor race at Saratoga, and then captured last Saturday's Jerome Handicap at Belmont by a neck.

Ordinarily, two performances like these would not be sufficient to make a horse the favorite for a race like the Marlboro Cup, even against a weak field. But Jaklin Klugman ran so fast both times -- a mile in 1:34 1/5 and seven furlongs in 1:21 3/5 -- that he indicated he is in extraordinarily sharp condition.

Still, Jolley has reservations, since the colt had a hard race just a week ago. "Noboby likes two tough races so close together," he said, "and that's certainly is a major concern. But Jaklin Klugman ran in the Kentucky Derby after a six-day rest, and so he may like his races close together."

Jaklin Klugman faces seven challengers in the mile and one-eighth Marlboro: First Albert, Tanthem, Glorious Song, Amber Pass, Temperence Hill, Hold Your Tricks and Winter's Tale. Of them, the filly Glorious Song is probably his most formidable opponent.

She is a paragon of consistency, having won 13 of 20 races in the last two years, but her most notable achievement was a loss -- a second-place finish behind Spectacular Bid at Monmouth Park last month. She is the only horse to finish within two lengths of the champion all year, although trainer Gerald Belanger has no illusions about the performance. "I think Spectacular Bid eased on in," he said. "He's the greatest horse I've ever seen."

The rest of the horses in the Marlboro have shaky credentials. Winter's Tale is topweighted with 123 pounds, but he was trounced by 14 lengths in his last start at Saratoga. "He came out of that race with very tender shins," said trainer Mack Miller. "He was so sore he couldn't walk. But we've worked on him 24 hours a day and he's responded. He's fine as of today." Still, that is hardly a ringing endorsement of the horse's chances.

Tanthem and Hold Your Tricks seem a bit outclassed, and both may find the Marlboro distance slightly beyond their capabilities. Temperance Hill, First Albert and Amber Pass finished 1-2-3 in the Travers Stakes at Saratoga, but that field was a weak bunch of 3-year-olds. None of them has ever run creditably against older horses.

Whoever wins the Marlboro Cup will know that he owes the victory to Delp's timidity. Spectacular Bid's trainer is the only man who thinks the 136-pound assignment could have hindered the champion.

Jolley would not have tried to challenge him, even with Jaklin Klugman getting an 18-pound weight concession. Belanger knows that Glorious Song is not in his class. Even Laz Barrera, the trainer of First Albert and a man never modest about his own charges, conceded, "Spectacular Bid could have run backwards and beaten my horse."