The 3-year-old gelding Grand Hombre, winner of all four of his starts by a combined 13 1/2 lengths, has been sold by owner/breeder Earle Mack to Sheikh Mohammed's Darley operation. The price is believed to be in excess of $1.5 million.Grand Hombre (Grand Slam--Santona, by Winning) won the Pennsylvania Derby (gr. III) in his last start Sept. 1. He broke his maiden in his debut at Gulfstream Park in March, then rattled off two victories in allowance company at Monmouth Park this summer.John Ferguson, bloodstock adviser to Sheikh Mohammed, said from the Keeneland September sale Thursday Grand Hombre would be pointed to the Breeders' Cup Classic-Powered by Dodge (gr. I).Dennis Manning trained Grand Hombre for Mack. The gelding was shipped to trainer Tom Albertrani's barn Sept. 10."(Sheikh Mohammed) has bought a wonderful horse," Mack said from his New Jersey office Sept. 11. "He conducted his business in a very forthcoming and professional manner. I compliment him on that, but I'm sad to lose a great horse."Mack credited Manning and racing manager Aaron Cohen for Grand Hombre's success. The gelding won the Pennsylvania Derby at Philadelphia Park by 5 1/4 lengths and defeated top 3-year-olds Toccet and Dynever in the process."I believe this is the best horse I ever bred," Mack said. "Sometimes you have to make difficult decisions in this business, and this is one of them."Mack still has the mare Santona, who is in foal to Chester House and who has a yearling by Honour and Glory. Mack also owned and bred the mare Paris Opera, who won nine stakes, all on the grass, and earned $638,225 in five seasons of racing from 1988-1992.