Wow, I looked up "Silacci's Speed Shop" and found this photo of that car in 2010, with a top:
Lower photo is Lloyd Silacci, who was 90 at the time.
Description says: "Porsche 914’s of any kind are not often seen at Bonneville. This is Lloyd Silacci’s Porsche racer seen at the SCTA-BNI Speed Week in August of 2011. This car featured 4 turbos, that's right – one turbo for each cylinder. Mr. Silacci (age 90) is a veteran racer, he has been racing for quite sometime. Lloyd knows a thing or two about going fast."
Also found another photo of Petaluma in 1958, showing Silacci's Speed Shop, among other things. That means he was part of the "American Graffiti" scene. So they may not have had a good year at Bonneville, but it's still plenty cool.