Asleep at the Wheel's "Pipe Dreams" is the unlikeliest collection of musical ingredients. It begins with a lonesome hillbilly fiddle, which leads into Ray Benson's craggy cowboy vocal with its unmistakable grin just below the lament; then Lucky Oceans brings in impeccable country studio pedal steel guitar. But after the first chorus, half-a-dozen fiddles and horns swarm up with precision swing jazz.

Before the album, "Collection Course" (Capitol SW-11726), is over, the 12-person band has played a Count Basie signature piece, a cajun stomper, a Randy Newman song, a rhythm-and-blues steamer and a country plaint.

But far from being a loose bag of unmatched items, all 10 songs are unified by a common Texas spirit: an irreverence for musical rules (there's steel guitar on the jazz; saxophones on the country ballads); a honky-tonk rowdiness; a willingness to throw everything into the pot for the hell of it; sweet fiddles and rough vocals; and an irrespressible smirk behind everything.

Most Oklahoman/Texas music is shaped by the honky-tonk bar challenge. Anything too serious is pretentious; anything limited to one genre leaves someone out; anything too polished is fake. Asleep at the Wheel plays this music better than anyone, but the new albums by Leon Russell and Jerry Jeff Walker as well as older albums by Delbert McLinton, Willie Nelson, Waylon Jennings, Doug Sahm, Freddy Fender and others indicate this regional tradition is still strong.

One of the most undiluted regional sounds still comes from the Texas/Oklahoma area, a no man's land between spheres of influence. Mexican dance music comes from the Rio river valley to the south; cajun and New Orleans R&B from Louisiana to the east; mainstream country from Nashville, and rockabilly and Stax soul from Memphis, both to the northeast; swing jazz from Kansas City to the north; and cowboy folk music from the desert and mountains to the west.

Few groups have juggled these balls as well as Asleep at the Wheel. To get enough arms to do it, they've doubled their personnel from the six on their first album. They've become a bona fide country and western orchestra, like their obvious model - Bob Wills & the Texas Playboys, the pre-World War II group whose members are still the heroes of Texas music.

Asleep at the Wheel illustrates a peculiar twist on the strange influence of geography. The core of the original group came from the suburbans of Philadelphia and Washington. They lived in Columbia, Md., Paw Paw, W. Va., and Berkeley, Calif., before moving to Austin, Tex. Instead of finding the environment and shaping an appropriate music, they shaped the music and then found the appropriate environment.

The group's outstanding musician is pianist Floyd Domino (a.k.a. Jim Haber, who has reportedly left the group since recording the album). Domino leads a furious charge through Count Basie's "One O'Clock Jump" with the sure, relaxed feel of the Count himself.

But where Basie's horn section came in with precisely measured blasts, Asleep at the Wheel comes in with sawing fiddles and a twangy pedal steel guitar bridging the phrases. The piece has the same momentum but an entirely different dialect.

The group's dominant personality, however, is lead singer and lead guitarist Ray Benson. With the charisma of a Louis Armstrong. Benson infuses each song with the broad grin that comes from having a good time doing a good job. On Louis Jordan's "Ain't Nobody Here But Us Chickens." Benson manages to sing both the straight-faced alibi and the implied devilment.

"Collision Course" is at once the most diversified and consistent record Asleep at the Wheel has produced. But like its predecessors, it fails to capture the high points they reach in concert. Benson in particular is a natural ham inspired by an audience.

The band's best musicians - Lucky Oceans, Domino, bassist Tony Garnier, fiddler Danny Levin, reedplayer Pat Ryan - try to top each other's solos when a crowd is there is impress. With the 6 1/2-foot Benson at stage center directing musical traffic, Asleep at the Wheel is the best song-based big band in the country.

Jerry Jeff Walker first won notice as the Bohemian folkie who wrote "Mr. Bojangles." But he couldn't sustain the folk-song writer image for long and soon returned to his origins as a Texas country and western singer with the emphasis on the western. His new album, "Contrary to Ordinary" (MCA 3041), contains no original songs but has 10 impressive covers on new Texas hybrid songs.

Walker voice isn't as distinctive as Benson's, but it is flexible enough to handle the full range of Texas music - from the Latin-tinged "Trying to Hold the Wind a Sail" to the bluesy "Saturday Night Special" to the pastoral "Till I Gain Control Again." He has assembled a tight seven-person band that includes Mexican horns, rockabilly guitar and traditional country pedal steel.

As Billy Jim Baker's title tune spells out, all the songs are about being "contrary on ordinary." Walker's persona on every cut is the rural roustabout, always a bit too drunk and a bit too impulsive for a lover to count on. Walker admits his drawbacks, but insists it's the only possible way to live and love fully.

Unlike the adolecent idealism of Tin Pin Alley, Walker's hinterland songwriters accept the flawed life and the flawed love as a given and try to make the most of it. Walker projects both his acceptance of flaws and his commitment to impulse in a persuasive voice.