You're probably fine, as long as you don't hear any engine pinging under load. If so back off the timing til it goes away. A lot of people think that advancing the timing above factory spec always provides more power. This is true in some engines, but not all. Case in point, I had my Datsun 2000 roadster engine chassis dyno'd with 105 octane gasoline. I started out with it advanced 10 degrees higher than factory spec. Re-tested at 5 higher and then the final test at factory spec. Factory spec produced more power and torque than 5 or 10 over.