‘Grammy Legends’--Sans Rock : Pop: After years of trying to improve its credibility with the rock world, the National Academy of Recording Arts & Sciences appears to be slighting the field again. Rocker Rod Stewart, scheduled to be honored, has pulled out of the show.

Grammy officials who have worked hard in recent years to improve the organization’s rock credibility may experience a sinking feeling as they watch the taping of the “Grammy Living Legends” television show tonight at the Pantages Theatre in Hollywood.

The two-hour program, which will air Friday at 9 p.m. on CBS-TV, was designed to honor artists “who have shaped and advanced music, influenced society and are still at the height of their careers.”

The problem?

No rock artists are being honored, yet two performers from the world of Broadway show music--Liza Minnelli and composer Andrew Lloyd Webber--are being toasted. The other honorees are pop/R&B; balladeer Smokey Robinson and country music veteran Willie Nelson.

The selections are likely to raise eyebrows among rock critics and fans, many of whom had finally begun to take the Grammys seriously--after years of complaining about the slighting of key rock performers in the Grammy process. Among the leading rock artists honored with Grammys in recent years: Bruce Springsteen, Prince and U2.

But it’s not as if the National Academy of Recording Arts & Sciences--which presents the Grammys as well as the “Legends” show--simply forgot about rock.

The academy had also planned to salute Rod Stewart on this program, but the British rock star pulled out shortly after the lineup was announced last month.

According to Stewart’s manager, Arnold Stiefel, the October announcement was the first time that he knew the identities of the four other honorees. The names that had initially been presented to him as possible co-honorees included such respected contemporary pop-rock figures as Bob Dylan, Paul Simon and Michael Jackson.

“I initially responded to the concept of the show when I thought it would be more reflective of the active, record-buying market,” Stiefel said. “But I lost interest when it became evident that the show was going in a different direction.

“The producers are pros and it sounds like they have have put together a bright and breezy variety show,” Stiefel added. “But Rod Stewart doesn’t belong in that format. It was the wrong show for him to be on.”

The “variety” issue was especially relevant to Stewart, who has recently reestablished his rock ‘n’ roll credibility with the smash “Out of Order” album after years of fighting a glitzy, jet-setter image.

Michael Greene, who as president of the academy has led the fight to improve the Grammys’ rock ‘n’ roll credibility, acknowledged that he was “pained” when Stewart dropped out of the show and it became clear that there would be no rock honoree.

“ Pain probably breaks new ground in understatement,” Greene said dryly.

Greene, a former rock musician, said that the academy initially considered replacing Stewart with another rock artist and even made a few calls regarding other performers’ availability, but ultimately decided to just spend more time on the show with the remaining four artists.

While the other honorees have sold millions of records, Minnelli is regarded primarily as a stage and film star and only incidentally as a recording artist. She has reached the Top 30 on the national sales chart with just two albums--the 1972 sound tracks to “Cabaret” and the TV special “Liza With a Z.” A new Minnelli album, produced by the Pet Shop Boys, is No. 128 in its third week on the chart.

Greene wouldn’t comment on whether other high-visibility female artists with a more substantial recording career, such as Barbra Streisand, Tina Turner or Linda Ronstadt, were approached for the show, but without naming names, he indicated that other recording stars had been offered a place in the show but declined.

“Any time you’ve got an inaugural show of any format, I think performers want to see how the first one comes out,” he said.

With “Living Legends,” the Grammy organization is following the lead of the Academy of Television Arts & Sciences, which bestows the Emmys and since 1984 has also presented the well regarded, but poorly rated, “Television Academy Hall of Fame Show.”

“Living Legends” evolved from the “Grammy Lifetime Achievement Awards” telecast, which aired to mediocre ratings in December, 1987. The program, which saluted Isaac Stern, Roy Acuff, Benny Carter, Fats Domino and B.B. King as well as eight deceased artists, was viewed in 16% of homes with sets in use. It finished 58th out of 81 prime-time programs for the week it aired.

“I thought the ‘Lifetime Achievement’ show was very important,” said Greene. “But a very narrow spectrum of the viewing populace watched it. When you do a show like that, you want to do it for a broad cross-section of the public.

“We decided that there’s just not that big an audience on broadcast television for performers in the twilight of their careers. We believed that doing retrospectives on artists at the same time that they are at the height of their powers is something that the general public would like to see.”

Several industry executives, however, have adopted a wait-and-see attiitude.

“What does it mean?,” said one top rock manager, who asked not to be identified. “We’ve already got the Grammys, which do mean something to the artists who get them. But this feels like they’re trying to manufacture a show to get some big names.”

Greene denied that the salute is intended as just another awards show. “There will be four one-minute segments where the artists will be given this Living Legend award, but the hook of this show is not the award,” he said. “The hook is live performance music, which broadcast TV has departed from for years and years. Producers and networks feel that unless music is constantly surrounded by ‘and the winner is,’ it’s not a valid concept.”

As for the selection process, Greene said, “There are probably 40 or 50 artists who meet the criteria. They’ve been influential for 20 or 25 years, they haven’t remained static, they are still active performing and touring.”

Greene said that the Grammy organization is losing money on the program the first year, but hopes to turn a profit in future years. The show has two other principal objectives: to honor veteran recording artists and to keep the academy in the public eye.