The 66 shop manual is available in reprint from the various Tbird suppliers and originals are for sale on eBay all the time. The shop manual is now also available on CD-ROM....which is nice because you just print out the page you need, then toss it once you're through. The electrical assembly manual is also available from the Tbird suppliers and shows you the original wiring diagrams used by Ford on the assembly line. For the shop manual and electrical manual try
www.thunderbirdconn.com. For the shop manual on CD-ROM try
www.tbirdranch.com. Good luck.