You need to purchase a Haynes Manual that is specific to your car.
Check with an older repair shop or go to the public library.
wiring diagramfor 1968 windshield wiper motor
I just bought a color 1966 impala wiring schematic on eBay that covers bumper to bumper. Read their full add in case u have extra options that the basic diagram may not cover. I am about to finish rewiring a whole 66 myself. Good luck, Oldskool Art Customs. 818 414 1968
http://www.moby302.co.za/wiring/diagrams.html
Go to nada.com and choose classic cars. That is a keeper.
answer
4 degrees before top dead center.
http://home.clara.net/hallvw/wire6870.htm
call year one and see if they have a book on it.
The best place to find a wiring diagram is in the Cadillac Shop Manual. You can find one on eBay in the $50 range. It gives you the wiring diagram and so much more. Mine is becoming threadbare from use.
http://home.clara.net/hallvw/vwwiring.htm has links to most air cooled vw wiring diagrams
It has a foam sealing tape to keep air from escapeing under the dash.