Lo and behold, I stumbled across this gold mine - https://library.stanford.edu/blogs/s...ine-are-online. There's a section dedicated to Porsche.

This is a bit of a gem. Who didn't love Can Am Racing?

Roll 1061: This is one of 3 rolls devoted to the first race of the 1973 Canadian-American Challenge Cup (1966-1987) at Mosport Park, in Bowmanville, Ontario, Canada. The race was won by Charlie Kemp, the series was won by Mark Donohue.
Here's Hans Weidmer in his 917/10 Turbo. According to my 'Porsche Prototype Era 1964-1973' book, the car was previously owned by Vasek Polak, who did some upgrades on the car over the winter of '72 for Hans, including making it turbocharged. Hans Weidmer campaigned it in '73. It had a bright orange and blue color scheme, lost here in b&w of course. He's really leaning into that corner.

Hans Weidmer, Porsche 917/10 Turbo, Mosport, 1973.