I've seen "Secretariat," and now the next racing film that should be made is about John Henry. Miss Kratchnut, take a letter. Address it to Harry Mogul, c/o Titanic Pictures, Hollywood, California.

"Dear Harry:

"Consider this a pitch for the next great horse racing movie. It's about John Henry, the grand old man of racing. You might remember him. Unwanted many times over, he finally was sold to a naive bicycle salesman who paid $25,000 and then watched him earn $6.5 million. John Henry had the legs of a broken-down chorus girl, the heart of Tyrannosaurus rex. He was not, as they like to say about horses on the backstretch, a pleasure to be around. He survived on oats and fingers. If you were ever caught in a stall with him, your first call was to a paramedic, your second to a mortician. If you had an apple in your hand, you might have stood a chance.

"John Henry didn't hit his prime until his senior years. He was Horse of the Year at seven, and again at nine. The key people in his life were an Irish trainer, an Irish veterinarian, an assistant trainer from Chile and an exercise rider who was Italian. I would suggest an international cast. Working title: John Henry. Overseas, you can call it Jacques Henri.

"Getting enough horses to play the lead will not be a problem. There are thousands of retired horses around, looking for jobs. Big horses, those taller than 15 hands, should not apply. The first time I saw John Henry run, in the 1981 Jockey Club Gold Cup, I thought he was a stable pony who had wandered onto the track by mistake. He was so small that he made his jockey, Bill Shoemaker, look big.

"Don't drown in your borscht, Harry, but we'll need a budget of about $500 million, give or take a mill. You remember the line in 'The Player,' in which a screenwriter, played by Richard E. Grant, makes a pitch to studio exec Tim Robbins: 'No stars on this project. . . Unknown stage actors, or maybe somebody English, like what's-his-name. . . This story is too important to risk being overwhelmed by personality.'

"Well, on this picture, Harry, we're going to take a big chance and sign up every star west of Westhampton. Money will be no obstacle (as long as it's yours). If I were casting director, these would be my suggestions:

"Owner Sam Rubin and his wife, Dorothy: Joseph Bologna and his wife, Renee Taylor. And don't forget to give Bologna that great Sam Rubin line, even if he didn't really say it. When Rubin closed the deal for John Henry and was told that the horse was a gelding, he said, 'What color's a gelding?'

"Trainer Ron McAnally: Alec Baldwin.

"Jockey Chris McCarron: Gary Stevens. You might ask, Why not have McCarron play himself? He acted in 'Seabiscuit.' Well, McCarron's too old to play himself. And Stevens, besides being younger, has more acting experience. He got more screen time in 'Seabiscuit.'

"Jockey Bill Shoemaker: Chris McCarron. Too old to play himself, McCarron is just right for Shoemaker.

"Jockey Laffit Pincay: Keith Austin. Keith Austin, you say? This is brilliant casting. Keith Austin played Pincay in 'Secretariat.'

"Assistant trainer Eduardo Inda: Benicio Del Toro.

"Exercise rider Looie Cenicola: Roberto Benigni.

"Veterinarian Jack Robbins: Robert Duvall.

"Phil Marino, the trainer when John Henry was a nobody: Adrien Brody.

"Debbie McAnally, the trainer's wife: Valerie Mahaffey (she was the wife of Charles H. Howard, the owner of Seabiscuit, in that movie). It might be a stretch, but I'd love to work in a scene where Debbie, before she married McAnally, went out with Joe Dimaggio.

"Lefty Nickerson, who trained John Henry in New York and was responsible for Sam Rubin sending him to McAnally in California: Harvey Keitel.

"Harold 'Bubba' Snowden Jr., the Kentucky breeder who kept getting John Henry back and kept unloading him: Ned Beattie.

"Modesty forbids, Harry, but I would be willing to play myself in a closing scene in which I visit John Henry in retirement at the Kentucky Horse Park, an apple in one hand and a banana in the other. The apple for John, the banana for Forego, across the shedrow. Forego loved bananas, but they had to be peeled.

"I'll work for scale, with no residuals. Have your people contact my people and we'll go from there."

Very good, Miss K. Sign it, Sincerely, Bill Christine, and send it special delivery. Use those old "Gone With the Wind" stamps. That will impress him.