A running gag has overtaken the running nags in the Hialeah backstretch. It has a half-interest in the $12 million Seattle Slew being insured for $4 million.

That's a joke, son.

Or is it?

Down at Barn N (as in never), they act as though they are laughing all the way to the bank. The "New Slew Crew" has three more members and their leader, Borwnell Combs, was quite willing to talk dollars and horse sense on a lovely Miami morning.

"We paid $6 million, cash, to the Taylors and Hills for a half interest in this horse," Combs declared as the 4-year-old colt's new trainer, Doug Peterson, completed the stable chores despite the presence of two television crews.

"Joe Layman, a lumberman from Washington, bought a quarter-interest and Franklin Groves, from Minneapolis, and I have the other quarter. That means Layman has 10 shares and Groves and I have 10 shares, at $300,000 each (share)."

This automatically gives the 20 syndicate shares retained by Mickey and Karen Taylor and Jim and Sally Hill a book value of $300,000 each. Thus: 40 shares for $12 million.

"My father (Cuzin' Leslie) put together the first syndication. The horse was Beau Pere, in 1947, for the movie man, Louis Mayer," Combs continued. "It was 22 years ago my father syndicated the first million-dollar horse, Nashua (for $1,251,200.) The idea was the same then as it is now; to spread the risk involved."

Slew will be leaving here soon for New York. His first objective is the Metropolitan Mile at Belmont Park Memorial Day. the 1977 Triple Crown hero appears to have recovered from the respiratory infection that kept him out of action here this winter. If all goes well, he will attempt to repeat as the horse of the year, then be retired to stand at stud at Combs' Spendthrift Farm in 1979.

Many commercial thoroughbred breeders, early in 1973, scoffed at the people who paid $190,000 a share for 32 shares in Secretariat. That was before Secretariat began his 3-year-old season. If $190,000 was high, how does Combs explain $300,000 a pop for Seattle Slew?

"The mathematics work out quite well," he replied. "You take $300,000 a share and divide by five (years) and that's really a $60,000 a year stud fee, and that's not exorbitant on today's market. We used to figure four, not five, to ascertain the share value. But the value of everything has increased in the horse business.

"Look at Secretariat. After he retired, and without the record this horse has, his shares sold for as high as $500,000. A close friend of mine, J. B. Faulconer, and his partner, Hillary Boone, bought into the original syndicate (at $190,000 a share) and after breeding twice they sold their share for $500,000, cash.

"People think of the $200,000 (a share) that I syndicated Wajima for and this $300,000 as asking a tremendous price, but Secretariat shares are selling now, despite the dismal start he had this past season, for $350,000."

Seattle Slew is a great-grandson of Bold Ruler, the sire of Secretariat.

Seattle Slew was sired by the now-deceased Bold Reasoning. His pedigree traces to Nasrullah on top and to Myrtlewood, Spendthrift's foundation mare, on the bottom. From Comb's point of view, Spendthrift may be about to get a bargain.

"You take racing performance and conformation and never discredit pedigree and, if you get the right mixture, you have a champion," he said. "It's the same for a champion sire.

"Slew has terrific soundness, exceptional bone structure. He can be bred to almost any type of mare. Let's see: you have Bold Reasoning to Boldnesian to Bold Ruler back to Nasrullah. So, consequently, the Nasrullah is far enough back in the pedigree that, if you have a mare whose grandsire is Bold Ruler or Nasrullah, you can still breed that mare without bringing things up too close.

"A lot of people feel they wouldn't want to breed closer than 3 X 3 (third generation) because Nasrullah is a very hot strain. But the late captain (Harry) Guggenheim did very well breeding some of his really good horses tight with Nasrullah. I recall he bred one horse to its own granddaughter. . . and got a runner."

Combs, Layman, Groves, the Taylors and the Hills undoubtedly will be more conservative in their selection of mares for Seattle Slew. Layman recently purchased the Fritch champion Theia, to go to the future stallion's court, and Groves spent a small fortune a few weeks ago for the former American champion Desert Vixen, who is also Seattle-bound.

The most interesting aspect of this syndication is the closeness of the corporation. It is a rather unusual arrangement, to say the least. Ordinarily, when an outstanding race horse is retired, a syndicate manager is named and that man goes into the open market to peddle the 32 or 40 shares costing so much a share.

Seattle Slew has been syndicated, but hardly in terms of establishing his open value. Five business interests have all of him, for better or worse, for richer or poorer, in sickness and in health, to love and to cherish -- for $300,000 a share, they say, for 40 shares.