This is a year when an owner does not need much of a 3-year-old to dream of winning the Kentucky Derby. Tonight actor Jack Klugman can dream.

His ill-bred colt, Jaklin Klugman, won the Stepping Stone Purse at Churchill Downs this afternoon in a fashion that suggested he could conceivably win America's most famous race next Saturday.

The Californian rallied to win the one-mile prep race by four lengths over Execution's Reason, and he did it with authority. His time was not dazzling, but it was not much worse than recent performances by the horses who are favored for the Derby.

Jaklin Klugman had established himself as one of the best colts on the West Coast, winning four of five starts as a 2-year-old before capturing the California Derby this season. His owner's celebrity status put him in the limelight when he went to the post for the rich Hollywood Derby in mid-April.

Given that opportunity to attain stardom, Jaklin Klugman laid an egg. He finished fourth, soundly beaten, and a more prudent owner might have kept him in California and bypassed the Derby. But Klugman hadn't spent a lifetime as a racing fan to pass up this opportunity, and he send his colt east.

Jalin Klugman vindicated that decision.

Jockey Darrel McHargue kept Jaklin Klugman under restraint, seventh in the field of 10, as he raced down the backstretch. He advanced along the inside as he approached the turn, but a tightly bunched pack of horses was battling for the lead in front of him. So as he came into the stretch, McHargue swung the colt out five horses wide to get running room.

Execution's Reason had taken the lead in the early stretch, but held it only briefly as Jaklin Klugman rushed past him and drew out through the stretch. Execution's Reason held on for second place by a nose over Withholding, who rallied strongly to be third.

"The race set up beautifully," McHagrue said. "I had plenty of horse left at the end. This was an excellent race to prepare him for the Derby and the horse is seasoning himself extremely well."

Trainer Riley Cofer said that the colt's preparations are now all but complete. "I'll walk him a few days, then blow him out before Saturday," Cofer said. Then he rushed to the director's room to telephone Klugman with the good news.

In describing the victory to the estatic owner, Cofer said, "We don't want to talk about the time." Jaklin Klugman had covered the mile in the terrible-sounding time of 1:38 3/5, but his performance wasn't as slow as it appeared.

The Churchill Downs track had been made very deep by early morning rains. Half an hour after Stepping Stone, a stakes race for 3-year-old fillies was run in the seemingly atrocious time of 1:26 3/5 for seven furlongs, which would translate into about 1:40 1/5 for a mile. So Cofer didn't have to apologize for his colt's clocking.

The result of the Stepping Stone further confuses the Derby picture. A field of at least a dozen horses seems likely to go to the post on Saturday. The cofavorites are Rockhill Native and Plugged Nickle, but these two have been less than awesome in their recent victories, and their margin of superiority over the rest of the pack seems narrow.

Some of the other candidates are Super Moment, who attracted attention with his fast finished in the Blue Grass Stakes on Thursday; Genuine Risk, who will probably be the first filly to run in the Derby since 1959, and Rumbo, a strong stretch-runner from California.

All of these horses may be as good as or better than Jaklin Klugman. But none will get so much prerace attention when the colt's owner comes to town on Monday.