Thanks to The Shell 4000 and Trans Canada Rally History Page,
"Scott Harvey and Rally Preparation" Sports Car Graphic May 1967 mentioned above is now available on-line as a scanned pdf.

Also on the same web page is Eric Dahlquist "How to Beat the Shell (4000) Game" Motor Trend '69 Yearbook, pp 160-5 with Scott Harvey. Includes a few tips for setup, a full list of equipment (spares) and where to stowe on the Barracuda, and good photos of protection of oil pan, gas tank, mufflers and differential. This one was new to me.