I would like to buy a 1966 data book
Tommy Statham
google what you're looking for and also check on Amazon. I just purchased a body shop manual for my 1967 from Amazon.
There's one on eBay right now with the optional specifications manual for $299
Reprints of Optional Specs here for $29.00
http://www.faxonautoliterature.com/1966-Cadillac-Optional-Specifications-Book-Reprint-P25777.aspx
Thanks guys. I made a deal on the original one on ebay