I got the DC header from CARID for a sale they had in the holidays for arount the same price. I've just never really trusted eBay's reliability. CARID still sells them but they are more expensive now.
Idk about a link to the harness cuz my dad who was a Grease monkey for over 15 years bought them for me back in '16 so I honestly have no idea.
Autolite plugs have a shorter gap then the OEM ones and therefore in my experience provide a more productive spark in the chamber.