Two men described by Montgomery County prosecutors as major figures in a countywide drug ring pleaded guilty yesterday to charges stemming from an operation in which narcotics were brought from Florida into the county and sold, according to deputy state's attorney Timothy E. Clarke.

Clarke said Harold Lee (Nick) Nickell, 37, of Bethesda, pleaded guilty to bringing drugs into the state and to conspiracy to distribute cocaine and methaqualone. Joseph Alfred Silvestri, 42, of Kensington, pleaded guilty to conspiracy to distribute cocaine and methaqualone and to possession of the two drugs, according to Clarke.

The two were arrested as part of a crackdown by the county on an alleged drug ring that stretched from the posh Promenade apartments in Bethesda to a racing-car engine manufacturing shop in Rockville, according to police.

Clarke said wiretaps had been placed on the telephones of the two men, and authorities heard them speaking about the purchase and sale of drugs, in coded conversations, during more than 1,600 telephone calls.

Under the plea agreement, the two may be sentenced to up to one year in prison, Clarke said. Sentencing is scheduled for July 19 before Circuit Court Judge John J. Mitchell, who accepted the pleas yesterday.