Rich Gentes indeed drove my father's Vermeil Offy sprinter for a NARC victory at Calistoga speedway in 1974- As reported on Hammerdownusa.com:

It was the last feature race won by an Offenhauser engine. Offenhauser was once the king of power for sprints and midgets. Gentes was driving the "Vermeil Offy". # 65. He had the lead in the feature for a while until the much more powerful Chevy of Lem Tolliver passed him. Then with about 5 laps to go Lem had car trouble and dropped out. Gentes then took the win. ...The last sprint car Main Event won by an Offy in the United States? ...37 cars, quick-time to Van Conett, dash to Andreetta, Heats to Bob Bloom, Don Melvin, Phil Pedlar, and Tolliver. ...KNBR radio personality, Mike Clary handled the trackside microphone.

Dad's car was the Travelon Trailer Special sprinter- a Shilala chassis with a 270 offy. Will post a pic soon-

Cya
Troy V