Republican National Committee Chairman Lee Atwater has named his best friend, GOP consultant Charles Black, to serve as his "designated spokesman" while Atwater continues to battle a brain tumor.

In a statement Friday, Atwater, 39, said: "My recovery is going very well. The doctors tell me that my tumor has stopped growing and is dying." He said he has begun to take a more active role in shaping party strategy, but he conceded that he has not been able to carry out "duties as the daily spokesman for the party, and that role is too important to let slip as we head toward Election Day."

There have been grumblings within the party that the GOP has lost its edge on taxes, civil rights and the savings and loan scandal and has not had a coordinated offense.

One Republican source said Black was specifically brought in to provide the White House with outside political advice.

Describing Black "as my best friend and political eyes and ears," Atwater said: "I've now asked him also to be my mouthpiece. . . . Charlie speaks for me and for the party."

Black's appointment comes a week after the summer RNC meeting in Chicago, the latest major party function Atwater has missed since he was stricken in March.

In his statement announcing the appointment, Atwater praised the RNC staff for its performance during the Chicago meeting. But he said the meeting "made clear to me the need to have the strongest possible spokesmen available to carry our message to the public on a day-to-day basis."

RNC press secretary Leslie Goodman stressed that Atwater will still be the "quarterback" and RNC chief of staff Mary Matalin will continue to handle day-to-day operations.

A Republican source suggested that naming Black "ends speculation about who is the next Lee. It gets the party through the November election before they have to begin the power struggle of who runs the presidential campaign."

Like Atwater, Black, 42, has strong ties to Republican conservatives. He is a partner in the political consulting firm of Black, Manafort, Stone and Kelly.

Ironically, as the Republican Party heads into the 1990 elections, its two most visible spokesmen -- Black and National Republican Congressional Committee Co-chairman Edward J. Rollins -- were not supporters of President Bush's election but rather were the two top aides in Jack Kemp's 1988 presidential campaign.