Dennis Manner was the engineer for Buick engines when these cars were produced, he might be able to help with your historical research. He's still around, as a technical advisor to the Riviera Owners Association on the 63-66 nailheads. Probably helps out in the BCA too, and has authored some tech articles in the GSCA GS-Xtra. Dennis Manner 11503 S. Linden Rd. Linden, MI 48451 (SASE for reply) At least that's how its listed in the ROA Riview newsletter.