SALEM – A Lynn man who was given a new trial on an eight-year-old drug case out of Lynn opted instead to plead guilty and received 3 to 51/2 years in prison with probation.Robert K. Nassor, 52, of 72 Washington St., #2, Lynn, pleaded guilty last month to trafficking over 14 grams of cocaine as well as two counts of unlawful possession of methadone and unlawful possession of OxyCodone before Judge Timothy Q. Feeley, but sentencing had been delayed.He was sentenced on Thursday to serve the state prison term agreed and given five years of probation when he is released with the conditions.Assistant District Attorney Michael J. Sheehan said that if he went to trial he would have established evidence that on Feb. 28, 2003 Nassor was arrested on Washington Street.Police confiscated more than 23 grams of cocaine from inside the trunk of a Pontiac he was driving along with some tablets of methadone and OxyCodone.Police also said they found a twist of cocaine on Nassor.