They used NGK - jap plugs for a jap engine. Not sure which plug it takes, but go to NGK's site and look them up. Nippondenso or Autolite are also good - I am running NGK dual platinums with Nology wires on my 1980 2.6 right now - running great. On Ngk plugs each number higher you go, the plug gets a 1/2 step colder.