Maryland's racing stewards today granted the chief of the state's race track security more time to investigate the running of the horse Dr. Peatoppy under the name of Sun Dandy on three occasions in February and March.

William L. Ramsey, a veteran investigator and head of the Maryland Thoroughbred Protective Bureau, said he had no idea when the probe will be finished. A meeting to discuss the matter had been scheduled for Friday, but that has been put off indefinitely.

"I'm sending all over the country for documents relating to the case," said Ramsey. "I've asked for a lot of information."

Ramsey is expected to question James Rowan, the horse identifier at Maryland's tracks; John Pappas, the official who takes blood and urine samples from winning horses; Coleman Blind, the substitute identifier who detected that the horse presented as Sun Dandy was incorrectly identified; Joseph Paladino, owner of both horses who Stifano claims sent the animals with incorrect nameplates on their halters, and Joseph Sierra, rider of the horse identified as Sun Dandy.

Both horses arrived in Maryland in mid-February in the closing weeks of the Bowie meeting. Stifano says each was marked with a nameplate on the halter and he assumed the names were correct.

When the horse he thought was Sun Dandy finished third in the second race at Bowie on Feb. 24, Stifano said he was surprised. Sun Dandy, he had been told, was a "crow"--race track parlance for an inferior horse. Dr. Peatoppy was said to have been far superior.

On March 6, Stifano again entered the horse he believed to be Sun Dandy in a $4,000 claiming race--the lowest level of competition in Maryland--and the horse won at 5 1/2-to-1 odds, he said. On March 17, Sun Dandy ran again at Pimlico, winning by five lengths at 5 1/2-to-1 odds, again at the $4,000 level.

While the horse he believed to be Sun Dandy was running, Stifano said he was resting the one believed to be Dr. Peatoppy after an operation on his hoof.

On March 31, the sound horse was presented at the paddock at Pimlico to run in a $6,500 claimer. This time, the regular identifier, Rowan, was on vacation, and Blind was substituting.

Checking the tattoo on the horse's upper lip, Blind noticed it did not match the number listed on the foal certificate for Sun Dandy. He called the stewards and they ordered the horse scratched. But Stifano questioned their action.

When Blind and Stifano checked the foal certificates in the racing secretary's office, it became apparent to Stifano, he said, that a mixup had occurred.

"I knew I was in trouble then," Stifano said.

He went to the stewards and explained what had happened, and they ordered an immediate investigation.

Both horses were suspended from racing by J. Fred Colwill, state steward, and Rowan was relieved of his duties as horse identifier by Robert Banning, racing commission chairman.