Received this morning:
Jeff,
Thank you for your email. I have check with Mark and he did have the car regularly serviced using synthetic oil for oil changes, but most of the time he says he used Pennzoil. Hope that answer helps.
Derek
Derek E. Moore
Curator
National Corvette Museum
350 Corvette Drive
Bowling Green, KY 42101-9134
Direct Phone: 270-777-4516
Fax: 270-781-5286
www.corvettemuseum.org