Boston guitarist/keyboardist Gary Pihl remembers the first time he heard that distinctive, orchestral guitar sound the classic rock band pioneered.

“I was driving down the street, and More Than a Feeling came on and I’m sitting there at a stoplight listening to it,” Pihl, 61, recalls. A car pulls up next to his. “It happened to be a guy I knew. My buddy jumped out and said, ‘Are you listening to this?’ This is the greatest stuff ever.”

Soon almost everyone would dig that first Boston album. More Than a Feeling, Long Time and Peace of Mind were the official Top 40 singles, but all eight songs on the record came to define classic rock radio and, at more than 17 million sold domestically, Boston remains one of the best selling debuts.

Founder Tom Scholz first crafted the group’s soaring sound in a basement in his Boston home in the early 1970s after graduating from MIT, years before the 1976 release of his landmark Boston album.

Pihl would become Scholz’s right hand man in the studio, on stage, and as vice president of Scholz Research and Development where the ubiquitous Rockman guitar amplifier was built in the 1980s.

“We were young and energetic and let’s keep going; that was the norm. I’d been in club bands since I was a teenager and played as much as possible. I played with Sammy Hagar, and that’s how I got to meet Boston. We opened up for their whole second tour across the U.S.,” Pihl says of Boston’s “Don’t Look Back” Tour in 1978.

When Hagar joined Van Halen in 1985 Pihl suddenly had time on his hands — and he would soon join a band that took a long time between projects. He wasn’t too concerned.

“I lost my gig and was looking for something to do. Tom warned me right away, ‘We’ll probably do a tour, and I’d like you to help me make the next album, which will take four years.’ So right away he was warning me it’ll take awhile. No surprise; it took longer than that, but I was thrilled with the outcome.”

Pihl’s first appearance on a Boston album was the track I Think I Like It on 1986’s Third Stage. His first full Boston album was Walk On eight years later and then Corporate America eight years after that.

A full decade has since passed, and Boston is 85 percent complete on its sixth studio release. For most acts, 15 percent remaining would mean you could hit download soon. But this is Boston.

“I always say next year,” Pihl laughs. “The old cliché, next year!”

Don’t expect any new songs on the tour opener at Hard Rock Live Thursday, but Pihl promises surprises. “We are playing songs that we haven’t played in a long time. To me, that’s the greatest thing. People come backstage or e-mail us and say, ‘That one song takes me right back to my first girlfriend or a special time with my family.’ That’s such a thrill to be able to do that.”

Boston performs at 8 p.m. Thursday at Hard Rock Live, 1 Seminole Way, near Hollywood. Tickets: $79, $69, $59 and $49. Call 800-745-3000 or visit www.ticketmaster.com. Follow @HowardCohen on Twitter.

Howard Cohen