Emilio Castillo had no idea his band would last 40 years. "I idolized The Spyders, a local [Oakland] soul band. They got hired to go to Sacramento and play a topless bar for a week. We were like, 'Wow, man, they're going on the road. If we could only get to Sacramento and play a topless bar, we would have made it.' " "My vision was [only] that far," added Tower of Power's co-founder and leader. "I had no idea what I could do. I just knew I loved it, and I would do it until I dropped. I far surpassed my wildest dreams." Saturday night, audiences can get a taste of the Oakland-based 10-piece band when it headlines the 17th annual Bump City Dance Party at the Radisson. Sammie-award-winning