This is the modern type thread and can be used with most modern plugs with M4 threads. I'm back on Tues.
4 Vintage Brass HT Spark Plug Terminals & 4 Thumbscrews Morris 8 Cowley Bullnose
2x Solid Brass Battery Terminal Connector Top Post End Clamps Set for Marine Car
For Mazda MX5 1.6 1.8 mk1 & mk2 89-05 HT leads spark plug ignition lead red
LANCIA FULVIA 1300 SILICONE HT LEADS SPARK PLUG IGNITION 7mm MAG WIRE RED KIT
For Mazda MX5 1.6 1.8 mk1 & mk2 Red 1989-2005 HT leads Spark Plug Ignition Lead