Looking for plugs to use for your brass-rod-modified or non-resistor caps? That’s the other article.

Unless you have changed your plug caps for non-resistor caps or removed the resistor in them, NGK D8EA spark plugs work well and are inexpensive (Amazon, eBay US, eBay UK, eBay AU). Note that they’re 11/16″, though in a pinch an 18mm socket can work. For an iridium plug (longer service interval), try the DR8EIX (Amazon, eBay US, eBay UK, eBay AU).