When I went to Europe in 1972 the Ferrari 312 PB cars were very dominant in the World Sportscar Championship.
Here is some information from Laguna Seca. 2016.
Here is the actual car # 15 driven by Ernie Pribe. 1971 Ferrari 312 PB.
There was also a 1972 Ferrari 312 PB # 87 driven by veteran driver, Bob Earl.
(Ken H and J. Adams photos..)
( Fine photo of both on the track from Tam's Old Race Car site.)
Ken H.