Chuck, good to talk to you the other day. I found my 66 Skylark assembly manual and it confirms the 66 battery cable numbers Walt posted. I also found a picture in the manual of the 66 GS battery cables, I will attach it, not to clear my old camera does not do well for this. I is page 12-18-2 of the manual and shows the +cable with the same number as Walt posted, the- has no number on the picture. If you look these are not spring ring ends. Based on this I am thinking 66 did not use spring ring.