Federal prosecutors tried today to establish that at least seven men acted as nominees or front men for friends of Gov. Marvin Mandel in an effort to cover up the friends' secret ownership of the Marlboro Race Track.

So secret was the friends' ownership that the accountant for two of them, Harry W. Rodgers III and William A. Rodgers, found during his efforts to reconstruct Marlboro financial ledgers for income tax purposes that obtaining information on the deal from the men was as difficult as "pulling teeth," according to testimony that was stipulated to by both the defense and prosecution today.

During this final phase of the prosecuiton's presentation in the political corruption trial of Gov. Mandel, federal attorneys spent most of the day reading the stipulated testimony rather than examining witnesses. Since most of the testimony had been heard in the first trial, aborted last December because of two outside attempts to tamper with the verdict, defense attorneys were able to agree with the prosecution on the substance of the testmony and thereby save time by reading the stipulations.

Defendants Harry W. Rodgers, William A. Rodgers, W. Dale Hess, and Ernest N. Cory Jr., are accused by the prosectuion of employing nominees to hide their ownership of the track so that their friend, Gov. Mandel, could, without suspicion, promote legislation that would greatly enhance the value of the dilapidated half-time track in Upper Marlboro.

The Prosecution alleges in the multi-count indictment that Mandel and his friends committed mail fraud and violated antiracketeering laws as part of a scheme to defraud the citizens of Maryland. In return for his actions, thee prosecution alleges, Mandel received some $350,000 worth of favors and gifts from his friends and codefendants.

Harold E. Wibberley Jr., president of a Hagerstown consulting engineer firm and a Mandel-appointed member of the board of review for the state Department of Natural Resources, one or three persons to actually take the stand today, that he was asked by Harry Rodgers to be a nominee and hide Rodgers' interest "for several months." Those months correspond to the period when the state government was deliberating on legislation affecting the Marlboro Race Track.

Other nominees testified - from the witness stand or through stipulations - that certain documents contained their signatures even though they themselves had not signed the documents.