very weak spark

You can download an entire free factory shop manual for '66 here:

http://www.mymopar.com/index.php?pid=31

direct linkey-doo

http://www.mymopar.com/downloads/servicemanuals/1966_Plymouth_Service_Manual.zip

Only deal with the above is that your viewer will show consecutive page numbers instead of Ma's "dash" numbering, so you have to play with page no's a bit

Sometimes easier, not always correct diagrams from same place

http://www.mymopar.com/index.php?pid=18

Direct link to diagrams

http://www.mymopar.com/downloads/1966/66DartA.jpg

http://www.mymopar.com/downloads/1966/66DartB.jpg