Before using ACDelco plugs you may want to read this.
http://www.allpar.com/fix/spark-plug-tubes.html
I was able to buy the NGK ZFR5N plugs at my local parts store. They had them in stock for $2.30 a piece.
I used a painless harness on my '57 D-100. It was great. Easy installation. Each wire is labeled the length of the wire to prevent mistakes. Buy/borrow a nice wire stripper and crimper. I have had zero problems and have been on the road 3 years.