Below are two of three of Barbara Bourbon's hardcore movies. From my research it appears they were all made in 1975. Although there are posts on this thread of "Dirty Western" and "Private Afternoons of Pamela Mann" I have obtained somewhat better quality versions. Unfortunately, my version does not include the rape scene in Pamela Mann.
California Connection: 1975
Dead link removed
AVI 1.95GB 720x544
Private Afternoons of Pamela Mann 1975
Dead link removed
AVI 1.89GB 720x544