Fresh Out of the ‘50s, They Do Fly-Rite : Pop music: Robert (Big Sandy) Williams’ band sounds less like rehashers of past music than discoverers of some eternal wellspring of high spirits.

If they had a time machine, the two co-founders of Big Sandy & His Fly-Rite Boys know where they would end up--back in the 1950s, when the world was just learning to rock.

With time travel unlikely, bassist Wally Hersom, 25, bandleader Robert (Big Sandy) Williams and the three other members of the Orange County-based group have done the next best thing. Their live shows and their just-released album, “Jumping From 6 to 6,� retrieve some of the best aspects of the roots-music past and pull them alive and gleefully kicking into the present.

Putting together elements of the rockabilly of Elvis Presley and Gene Vincent, the Western swing of Bob Wills and the honky-tonk music of Hank Williams and George Jones, Big Sandy & His Fly-Rite Boys, who play tonight at Jacks Sugar Shack, sound as if they themselves had just stepped out of a time machine.

Their sound is an authentic representation of its period-piece inspirations, yet the delivery is so infectious and brimming with vitality, native enthusiasm and assurance that they sound less like rehashers of past music than discoverers of some eternal wellspring of high spirits. (Drummer Bobby Trimble, guitarist Ashley Kingman and steel guitar player Lee Jeffriess round out the lineup.)

Williams, 29, is the key to the band’s ability to sound fresh while sounding old. His singing is smooth, rich and creamy, full of unstudied, unforced pleasure. He never strains for an effect, but sounds natural and completely at home with everything he sings. Much of it is original material with simple, innocent lyrics about the pleasures of rocking or the human comedy of falling in love, getting dumped, then starting the cycle all over again.

The question of whether his band is creating something fresh or just exhuming the past “only comes up in interviews,� Williams said recently during lunch in Orange.

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He is a genial, soft-spoken man who forms his thoughts slowly and deliberately, then unleashes them in staccato bursts. “People can be into any new band, (yet) they can come and see us and enjoy it. To these kids, it’s new music. Our point of view is (to play) as if this is all new music.�

Williams and Hersom both began playing 10 years ago in bands on Orange County’s rockabilly revival scene. They launched Big Sandy & His Fly-Rite Boys in 1988. There followed two albums on tiny labels, several trips to England and Europe, and a monthlong stint in 1992 as Morrissey’s opening act on a U.S. tour. Dave Alvin, the respected Los Angeles singer-songwriter, became a fan, helped the band land a deal with HighTone Records, and produced the live-in-the-studio sessions for “Jumping From 6 to 6.�

“The recording was four days in a row, 11-hour days, cutting live,� Alvin said. “Most singers I’ve known and worked with or seen in the studio, as professional as some of them are, will bitch or lose it after several hours. Sandy never complained, and maybe once or twice hit a flat note.�

If that time machine did exist, Big Sandy and company could go back to the mid-’50s and stand a very good chance of making it big with songs like “Hi-Billy Music,� a thoroughly engaging and catchy Williams original.

But as things stand, Hersom acknowledges, “there’s no set niche they can fit us into� in marketing the album. So tireless touring, not time travel, is in the offing. Said Hersom, “If we can get it out there in the stores, and we’re out there playing and in people’s faces, they’ll hear it and like it and it’ll create a market.�

* Big Sandy & His Fly-Rite Boys play tonight at Jacks Sugar Shack, 8751 W. Pico Blvd., 9:30 p.m. $5 cover. (310) 271-7887.