This year, The Clarks celebrate 40 years as a band — and they’re still selling out shows, as with their Friday night engagement at The Oaks Theater in Oakmont.

For a certain strand of Southwestern Pennsylvanian, The Clarks have become a part of the fabric of the region, much like yellow bridges and chip-chopped ham. They’re local folk heroes and they’ve created a Pittsburgh hymn in the form of somber sing-along song “Penny on the Floor.”

Keeping things in the Pittsburgh family, Brownie Mary’s Kelsey Friday opened the night with the musical aid of Rick Witkowski and Jack Delaney. Friday’s voice has gained a bit of grit and smoke, lending itself well to the more acoustic nature of the show, especially on her cover of John Prine’s “Angel from Montgomery” (though hers was more fittingly in the style of Bonnie Raitt’s version).

But she pulled out her own classics, too, slipping easily into Brownie Mary’s “Lessons.” She even gave Witkowski a chance at the mic, and he sang an uplifting rendition of B.E. Taylor’s “Vitamin L.”

The atmosphere ratcheted up a notch when The Clarks took the stage, tearing into a two-dozen-song-long set with “True Believer,” a raucous tune from their 2009 album “Restless Days.”

Lead singer Scott Blasey is 61 now, but his resonant voice sounds just the way it did on records three decades ago (maybe because he’s drinking tea onstage these days). He really belted out the pre-chorus on “Gypsy Lounge,” earning some cheers from the crowd.

But he wanted to share the vocal work, too.

“This is a sing-along,” he told the crowd before launching into the first lines of “Born Too Late,” one of the most well-known songs from the band’s biggest album, 2000’s “Let It Go.”

They interspersed those crowd pleasers with album cuts from throughout their career, hopping from the ebullient ’90s rocker “Mercury” to the wistful title track of the “Restless Days” album, a song that Blasey said was an ode to his hometown of Connellsville, Pa.

Friday night’s show definitely had some less-fun songs sprinkled in, but overall it was just a summer Saturday night of a set, full of the kind of songs you want to blast as you drive into a July sunset. One such tune is, of course, “Shimmy Low,” with its “woo-hoo-hoo”s and shoutable chorus. But another was a more recent addition to their catalogue, “Dance on the Bar,” a nostalgic anthem that highlighted the genuine quality in Blasey’s voice — it sounded like he was sitting there telling you a story about the glory days.

After singing the fast-paced “Let It Go” track “Highwire,” Blasey expressed his gratitude for the band’s friendship with Kelsey Friday and brought her back to the stage to help him sing “Roses.”

“Fast Moving Cars” was another standout, a quieter tune that Blasey said he loves.

“I was bummed out when I wrote that song. That’s where all the best ones come from,” he told the audience.

The band followed up “Brand New” — a request from a sign in the audience — with the poppier breakup song “On Saturday,” which had the crowd singing along once again. After that came recent single “Supernatural,” which was on their EP “Echoes from The Pitt,” which was released in January. The song has a classic rock vibe, with the mournful wail of Rob James’ guitar spiraling throughout.

Speaking of “Echoes from The Pitt,” the EP came after The Clarks had a song featured on the hit HBO Max series “The Pitt.” That song was “Better Off Without You,” another of their popular breakup anthems. I’m sure that by now they could play this song in their sleep and it would still bring the house down.

At the song’s close, someone in the crowd yelled, “Give us more!” Blasey was happy to oblige.

“You want more? You’ve got more!” he joked.

“Honestly, it is the wildest thing in the world, I feel better than I ever have,” he added, reflecting on the long career that the band’s members have enjoyed together.

Before playing “Irene,” another showcase for the band’s talent for earnest, softer songs, Blasey talked about how the song started out being about the late country singer Mindy McCready and ended up being a tribute to his father, as he was in hospice as Blasey was writing it.

“Every time I do this song, I think about my mother and father,” he said.

They added their own flavor to Elvis Costello and the Attractions’ tune “(What’s So Funny ‘Bout) Peace, Love and Understanding” just before the grand finale: “Cigarette.”

Blasey graciously thanked the crowd and bid his farewell with perfect timing as James fired up the dark opening guitar riff, and I’d say about 80 percent of the crowd knew all the words — especially “biiiiig hair.” As the band began to wind, whirling around with the last chords, Blasey pulled out his falsetto for a few lines of The Isley Brothers’ hit “It’s Your Thing.”

Four decades in, and The Clarks show no sign of slowing down — and Pittsburgh shows no signs of getting tired of them. In fact, the band and the crowd may be better than ever.