It's not in Petaluma any more. It is now held at Sears Point Raceway. The Sonoma-Marin County Fairgrounds wanted something likt $5,000 for Wine Country Mopar to hold their event there, so they moved it to the racetrack and have dragraces in addition to the show. However over the past few years turnout has dropped like a rock. Last year there was only like 50 cars and about 5 swap meet spaces and most of the racers didn't drive Mopars because it is part of the Summit ET series. I didn't even go this year after how bad the event was last year. It was a couple of weeks ago, they moved it from August to June.
