At straight-up 3 p.m., the appointed hour, a man on the other end of the line announces himself: “Heyyyyy, it’s Southside!”

And so begins a spirited 40-minute conversation with one of rock ‘n’ roll’s most undervalued artists, Southside Johnny Lyon, who has fronted a horn-heavy R&B band called the Asbury Jukes for more than three decades. After his first troika of LPs, released in the latter ‘70s on Columbia, fell short of commercial expectations — especially in light of the concurrent rise of his Jersey shore compadre Bruce Springsteen — Southside and company focused mostly on touring.

They don’t do the road-dog slog of the old days, when 250 dates a year was the norm, but the Jukes still cover plenty of turf. And they try their level best not to let performing get stale. “I’ve never wanted to just go out and play the songs,” Southside says. “I need to find that nugget in the middle of the night, where the audience clicks and is really there, and we’re all in that night, in that moment.”

With an eight-piece backing band (including four horns), Southside, 60, shouts and wails and dances and sweats and jokes his way through sets that put a premium on spontaneity — sometimes taken to extremes. “I was drivin’ to a gig one time and I heard ‘Walk Away Renee’ on the radio, the Four Tops version,” Southside recalls. “So on stage that night I just started singing it. [Guitarist] Bobby [Bandiera] started playing it and we did it as a duet. A couple nights later, the drums and bass came in — they’d gone over it a little bit — and we added it to the set; ended up putting it on a record. When it works, it really works — but it doesn’t always work.”

Southside Johnny is a gifted singer, with a natural soul moan, an extra gear that brings out the grit, and a knack for calibrating his voice to fit the song, be it a jazzy ballad, a Stax-styled stomper like “Talk to Me” or Sam Cooke’s good-times anthem “Having a Party.”

For those other than his devoted cult of fans, Southside is perhaps best known as the guy who got left in Springsteen’s dust.