The standard tire was a bias-ply 8.85-15 BSW. The 8.85-15 WSW was optional at extra cost. An optional 225R15 radial WSW became available after the start of the model year. The attached thread from AACA shows the details on the radial.
Was not able to track down the whitewall width or tire brand. Normally GM used more than one tire brand to avoid supply problems from the tire makers. With enough searching, info will probably turn up from an original spare that somebody has.
I have the Automobile Manufacturers Association (AMA) Specifications publication issued 9/1/66 which lists the only tire size available as 8.85-15 bias ply. I have the revised specifications dated 12-15-66 which shows 225R-15 radials available. My question is -- will the AACA judges accept this r...
The 1 inch white wall was pretty much a standard across the industry at that time. The 8.85-15 morphed onto an L 78-15. The 225-15 radial sizing continued until the P metric system was adopted. The sizing did change somewhat so the closest radial size in height today is actually a 235/75-15.