In the original liner notes to the Beach Boys' four-CD set, "Pet Sounds -- The Pet Sounds Sessions," Brian Wilson writes: "Now, this new repackaging and box set of Pet Sounds' -- it feels good in my heart. It's like, right on time, you know what I mean. Of all the things we could be doing in the whole darn world, we're here, kinda like, slowly, just getting this Pet Sounds' thing to come into being, you know, and it's really quite amazing."

Indeed, the box set devoted to what has been hailed as one of the greatest albums of all time will likely include the original mono mix, a first-time stereo mix, and tons of session tracks showing the work in progress, as well as one "Pet Sounds" featuring the instrumental tracks without vocals, and one of vocal tracks without instrumentals.

Unfortunately, what Brian Wilson may be feeling in his heart right now is . . . heartburn. The Capitol set, which was to have been released May 15 -- the 30th anniversary of the original release -- was suddenly postponed until late June and has now been taken off the schedule completely. Phil Sandhaus, Capitol's vice president of strategic marketing (a k a "catalogue sales") said Friday that the label would decide "in the next two weeks if it will come out this year." An October release, close to the crucial holiday season, is the most likely.

Beach Boys manager Elliott Lott concedes that the set is an intricate project that was rushed and ran late, but points out that it's also a "Beach Boys project" that ran into problems "in areas where {the band} had approval rights."

There seem to be two major conflicts. One revolves around how the rest of the Beach Boys are portrayed in the set's extensive booklet, which details what everybody has known for 30 years anyway: that "Pet Sounds" was Brian Wilson's creation and that the group (which he'd stopped touring with in early 1965 to concentrate on composing and production) was just a tool, albeit a very important part of the finished product.

Wilson himself points out that he did most of the singing on "Pet Sounds" because "it seemed like it was my time to step out and do something." All the backing tracks and most of the lead vocals were finished by the time the Beach Boys returned to Los Angeles from a Japanese tour.

Though Carl Wilson, Alan Jardine and dozens of musicians, engineers and other participants in the "Pet Sounds" sessions were interviewed, singer Mike Love is noticeably absent and the Beach Boys' role is generally played down in the notes. Capitol has commissioned new liner notes from Smithereens drummer Dennis Diken, a music historian and collector whose own band records for Capitol.

The other problem apparently revolves around the first-ever true stereo mix of "Pet Sounds," done for the box set by Mark Linett under the guidance of Brian Wilson (the old "Duophonic" version was barely simulated stereo). Some of the backing vocals were dropped out and some of the vocal bridges were altered because no mono track existed: For instance, on the bridge to "Wouldn't It Be Nice," Love's lead vocal could not be used in the stereo mix and was replaced by Brian Wilson's vocal.

"On the two-track they couldn't isolate Mike," says Lott, who believes the substitution "changes the song dramatically. The question is: Is this the best stereo mix? We'd prefer {the stereo mixes} to be as identical to the mono tracks as possible." Capitol will be issuing a remastered version of the original mono mix separately; the stereo mix would be available only as part of the box set.

"The Beach Boys apparently didn't get the track selections until late in the production phase, and they all had misgivings about how Capitol envisioned it," says Timothy White, managing editor of Billboard magazine and author of the Beach Boys biography "The Nearest Faraway Place."

White says that "the Beach Boys operate as an entity within a committee framework, as opposed to Brian doing things on his own." As a result, the Beach Boys are both a band and a family in which "everyone has their own raft of concerns. It's a very complex organism, an endlessly complex little tea party."

Though Billboard has twice had to reschedule special tribute sections focusing on "Pet Sounds," White diplomatically points out that "the anniversary is for a whole year," which allows some leeway.

One potential problem exists because of the delays: piracy. Advance tapes and xeroxes of the original liner notes were sent out to critics in anticipation of the May 15 release. Some entrepreneur could put out an alternative set before the Capitol troubles are resolved (which would technically be counterfeiting rather than bootlegging since it would replicate the Capitol set). "That's always that worry when you send out advance music," says Capitol's Sandhaus. "Of course we're concerned, but we'll just have to deal with that."

Those who can't wait until Capitol and the Beach Boys straighten out their affairs can turn to Seattle's Sub Pop label, which has just issued a limited-edition seven-inch vinyl single featuring three previously unreleased tracks from the "Sessions" box, as well as a picture sleeve with alternative shots for the original "Pet Sounds" cover shot at the San Diego Zoo.

Sub Pop, the feisty indie label that was first home to Nirvana and Soundgarden, was approached by Capitol to release the single (only 10,000 copies will be available worldwide, half of them stateside) in conjunction with the box. It now finds itself with the only "Sessions" material on the market. The single features an A-side with the stereo mix of "I Just Wasn't Made for These Times" and a vocals-only "Wouldn't It Be Nice," backed with the stereo backing track to "Here Today."

This isn't the first time "Pet Sounds" has encountered difficulties (thought it has fared better than 1967's never-released "Smile" album). Back in 1966, Capitol didn't seem to want to get behind the album that was inspired by the Beatles' "Rubber Soul" and would in turn inspire the Beatles' "Sgt. Pepper's Lonely Hearts Club Band." Just two months after "Pet Sounds" was released, Capitol flooded the market with "The Best of the Beach Boys," ending any momentum "Pet Sounds" might have been developing.

The now-classic album peaked at No. 10 that year, and was the band's first album of new studio material not to achieve gold status (500,000 copies); in fact, 30 years later, "Pet Sounds" has yet to be certified gold. Maybe the album just wasn't made for those times.

As for "The Smile' Era" box set that was being talked about in February 1995, it probably won't be coming out. And the "Pet Sounds" box's possible bump to October also means a bump into 1997 for another project -- a set focusing on production of the classic single "Good Vibrations."

In the meantime, the Beach Boys will next appear on a pair of country tributes, providing harmonies as various country stars explore their songbook: Willie Nelson doing "Warmth of the Sun," with Brian Wilson producing; James House driving the "Little Deuce Coupe"; Tammy Wynette stuck "In My Room"; Lorrie Morgan counseling "Don't Worry, Baby"; and more from the likes of Colin Raye, Sawyer Brown, Toby Keith, Ricky Van Shelton and Rodney Crowell. The Beach Boys joined many of these singers in concert at the recent Fan Fair, and there will be specials on Disney and CBS in the fall.

CAPTION: Squabbles over credit and remixing have pushed back the release of the Beach Boys' "Pet Sounds Sessions," a 30th-anniversary four-CD retrospective.