JAKE AND ELWOOD Blues have finally hit the big time. The two orphans from Rock Island, Illinois have survived years of arduous life on the road to find sudden fame and fortune in New York and L.A., proving themselves to be players, alas, very much ready for prime time.

John Belushi and Dan Aykroyd, of NBC's Saturday Night and other fame, have released a gem of an album under the guise of the Blues Brothers, an act first spawned to warm up Saturday Night studio audiences a year or so back. Perhaps you have caught a couple of their subsequent appearances on the show, decked out in black suits, fedoras, and shades that would have done a G-man proud (circa 1962). Steve Martin, who guest hosted one show on which the Brothers performed, was sufficiently impressed to ask them to open eight shows for him in L.A. last September. Belushi and Aykroyd agreed, and the results of those labors have been captured on Briefcase Full of Blues.

The striking thing about this album is that, despite its comic appearances (for instance, the gloriously cheesy cover photos), it does not come across like Saturday Night, or Animal House, or even the National Lampoon's Lemmings. The music itself is, for the most part, surprisingly straightforward. With the immediate intention of recording the September concerts, Belushi and Aykroyd took the opportunity to assemble a band of stellar musicians who would back them up in thoroughly professional style. Their collective sound virtually overshadows the few attempts at genuine comedy, although this remains strictly a good-time album if there ever was one.

The songs themselves are fantastic. The first high spot is an absolutely perfect version of Floyd Dixon's "Hey Bartender." Belushi snarls, "Hey bartender, hey man, lookie here/Draw one, draw two, draw three, four glasses of beer," as the horn section, arranged by James Brown alum Tom Malone, blasts away behind him. Aykroyd has one of his better harmonica solos, followed by some ringing guitar by veteran bluesman Matt "Guitar" Murphy.

There really isn't a weak song on the rest of Side 1, either. "Messin' With the Kid" features some fine guitar work by Murphy and especially Steve Cropper, the legendary Memphis session man, producer, and mainstay of Booker T. and the MGs. Belushi smooths out his vocal delivery a bit in "Almost," and Tom Scott of the L.A. Express handles the sax break as the rest of the horn section punches away. Next comes Aykroyd's only solo number, a wonderfully obscure bit of nonsensical babbling called "Rubber Biscuit" which is, believe it or not, quite faithful to the original version. Murphy takes the spotlight in the classic 12-bar "Shot Gun Blues," delivering some sizzling runs as Belushi moans, "I'm gonna take a shotgun, baby, disconnect my brain."

SIDE 2 opens with an amusingly reggae-fied version of King Floyd's "Groove Me." Belushi does not do the most convincing Jamaican imitation in the world--he almost sounds Irish in some places--but the song succeeds nonetheless. "I Don't Know," which follows, is very funny and includes some extremely suggestive lines from Belushi ("Baby, you know when you bend over I see every bit of Christmas, and when you bend back I'm looking right into the new year."). On "Soul Man" Cropper delivers the same great riff he's been playing for years, and fellow MG Duck Dunn's bass line is downright thunderous. " 'B' Movie Box Car Blues" and "Flip, Flop & Fly" are fine, though not up to the standards set by the album's other tracks.

Most of the comedy on this record is confined to little asides slipped into or between songs. Of course, the supposed saga of the Blues Brothers' road to the top, as told on the back cover, and the appearance and stage act of the band are intended to amuse. Some of the songs are in a light vein, as well. But Belushi and Aykroyd did not record Briefcase Full of Blues as a comedy album. Belushi is clearly out to prove that he is a singer, not just a comedian who sings a little. His performances here, along with his renditions of "Louie, Louie" and "Money" on the Animal House soundtrack and his famous Joe Crocker imitation, show just how good a rock and roll singer he can be.

Aykroyd, at least on record, plays second fiddle to Belushi, who first conceived the Blues Brothers act. Aykroyd's harmonica fills are never less than adequate, and are quite often strong. Unfortunately, they tend to get lost in the mix, marring the otherwise excellent production by Bob Tischler.

This is, presumably, only the beginning for the Brothers. A movie is rumored to be in the works, scripted by Aykroyd. If we are lucky, there will be more Blues Brothers albums to follow, perhaps (is this too much to hope for?) with the same superb band. Meanwhile, heed the words of John Belushi, a.k.a. Joliet Jake: "I suggest you buy as many blues albums as you can."