O.C. POP MUSIC REVIEW : Sisters at Best When Relating Passion, Grit : The Sweethearts of the Rodeo shine with invigorating country music when not engaging in pre-packaged material.

One sister put bugs in the other’s hot chocolate. They borrow each other’s clothes without asking. And Kristine Arnold and Janis Gill--collectively the Sweethearts of the Rodeo--grew up singing with that special sibling harmony, the unmistakable bonding of kindred throats that keeps asserting itself in popular music, from the Everly Brothers to the Neville Brothers.

Those revelations about the insects and purloined dresses came in “Sisters, Best of Friends,” one of eight new songs introduced in the Sweethearts’ early show at the Crazy Horse Steak House Monday night. Throughout the 18-song set, the sisters did indeed display a playful friendship, which was more evident in spite of their pre-programmed bickering onstage than because of it.

Like a great many country acts, Arnold and Gill lard their show with scripted banter; they are less skilled than some at making it convincing. They also included a few of the soulless, weightless songs that the Nashville song mill churns out day and night (unfortunately, the Sweethearts’ next single, “Hard-Headed, Soft-Hearted Man,” due shortly, appears to be one of these). The sisters sang them with an appropriate lack of zeal.

But far more often, the sisters and their four-piece band did justice to their name, borrowed from the Byrds’ 1968 “Sweetheart of the Rodeo” album, one of the first country-rock ventures (the cover art of the sisters’ most recent album, “Buffalo Zone,” is a takeoff on that Byrds’ LP cover). Much of their material has the invigorating spunk of California-bred country, and when the songs thus warrant it, the two sing with affecting passion and grit.

Arnold sings lead, while Gill (the wife of country singer/writer Vince Gill) sings harmony, plays acoustic guitar and writes or co-writes much of the material. The two grew up in Manhattan Beach before relocating to Nashville and taking off with their 1986 debut “Sweethearts of the Rodeo” album, which yielded five country hits, quite a feat for a disc with only eight songs on it.

Some of those hits were in Monday’s set, including a hard-driving version of “Chains of Love,” which had a vocal fire missing on the record. At the other extreme of the Sweethearts’ range, Rodney Crowell and Hank DeVito’s ballad “I Can’t Resist” offered a harmony vocal with the haunting, yearning quality of the Everlys’ best efforts, a comparison further cemented with their hit version of the Everlys’ “So Sad (to Watch Good Love Go Bad),” performed during their encore.

Bravely, the sisters set aside some of their bigger hits, including their covers of the Everlys’ “Hey Doll Baby” and the Beatles’ “I Feel Fine,” to introduce untested songs from their next album, due in September. They also sang the non-hit but beautiful, border-spiced “Como Se Dice (I Love You)” from “Buffalo Zone,” and introduced their version of the Elvis obscurity “Paralyzed,” which featured a wild, brilliant rockabilly guitar solo from Kenny Vaughan, played on a ‘50s Sears-Silvertone electric.

The new songs included “Between a Rock and a Heartache” (the gutsy emotion in Arnold’s voice won out over a glib lyric line); “Watch Me Run,” an assertive country-rocker with a Desert Rose Band feel; the Gill-composed “I Don’t Stay Down for Long,” which borrowed some uh-hunh-hunhs from Elvis’ “Good Luck Charm”; the aforementioned “Sisters, Best of Friends,” and “He’s the Man of My Dreams.”

That last song, Arnold said, was written by Gill about her husband, Vince; Arnold added that she thinks about her own husband while singing it. It’s easy to understand how many women might find a familiar person in its lyrics: “He can watch TV for hours and hours / He never thinks of bringing me flowers / But he’s the man of my dreams.”