There are not many rock bands that have lasted 50 years without taking a major break or losing their key leaders. The Rolling Stones and The Who spring to mind as the most prominent of those fortunate die-hards. But Emilio Castillo is proud to note that he and co-founders Stephen “Doc” Krupka and David Garibaldi have kept their band Tower of Power going strong as well.

In fact, the horn-driven funk legend is currently engaged in a year-long world tour celebrating its five decades as a band, bringing the show to the Libbey Bowl in Ojai on Friday night. Rather than simply resting on longtime fan favorites, however, the band is promoting its newest 14-track album, Soul Side of Town, which has fans just as excited as ever.

“We knew we were coming up on our 50th anniversary, so one of my old managers suggested this isn’t just the time to throw together 12 songs, but to make one of the finest albums of our career,” says Castillo. “He said record way more than you need and pick the best 12, like Michael Jackson used to do. We had to go in and out of studios between tour dates and we recorded 28 tracks in all.

“When we signed to Mack Avenue Records they wanted to put it all out. We said no, let’s put out one and then put another out. We have another fully recorded, mixed, sequenced and ready to go before the end of this year.”

Since its formation in Oakland in 1968, the 10-member Tower of Power has forged a reputation as an ace band fluent in all realms of soul, rock and pop music with the sophistication and punch of a jazz big band. From its 1970 first album East Bay Grease, the interracial band became a standout of the Bay Area music scene that included pioneering like-minded bands such as Sly and the Family Stone, Cold Blood, Graham Central Station, The Pointer Sisters and The Sons of Champlin, plus such rock-oriented outfits as Santana and Journey.

Along with classic recordings, Tower of Power’s five-piece horn section — known for its power-packed punch with two trumpets, two tenor saxophones, plus a baritone sax — became much in demand for studio sessions and live gigs. Among the hundreds of artists its members have worked with are Elton John, Little Feat, Rod Stewart, Smokey Robinson and Aerosmith. But their most essential collaboration came with Huey Lewis and the News in that band’s mid-’80s heyday.

“We did a lot of their recordings and toured for years, and it was much more than just a gig, because we were close personal friends and we saw eye to eye on a lot of things,” says Castillo. “I said, ‘if you promise you will promote Tower of Power at every turn, interview and prominently onstage, we’ll do the tour.’ We were sort of at a low point and he did that. . . . Huey named each of us by name, gave us featured spots in the middle of shows, and talked about us in every single interview. . . . He singlehandedly resurrected our career.”

Another factor in the band’s revived success at the time was Castillo’s decision to become sober after years of drug and alcohol abuse. Now he notes that the band follows key rules of healthy living in order to maintain a rigorous tour schedule.

“We’re careful about having good hotels, enough sleep, watch the food we’re eating, and pray together before we get on a plane or on stage,” says Castillo. “If someone needs space, we give them space, or encouragement. It’s a family situation and that’s how we approach it.”

“In terms of the live performances, we have incredible fans,” he continues. “We may not have millions of fans that some of the huge stars have, but we have lots of fans worldwide and they are really nutcases for Tower of Power. The kind of energy we get from the crowd helps us get to the best performance we can.”

Tower of Power performs on Friday, Aug. 23, at 7 p.m. at Libbey Bowl, 210 S. Signal St., Ojai. For tickets or more information, call 888-645-5006 or visit libbeybowl.org.