My home inspection of Speedmaster heads

What plugs are you thinking? Here's what SM recommends: "SPARK PLUGS
Our heads require the use of 14mm. x 3/4 reach 5/8 hex gasket seat sparkplugs. Some recommended plugs are; NGK BCPR6ES or R5671A-7, Champion RC12YC, Autolite AR3923 or AR3924. Remember these are for mild street engines. Higher compression or boost requires colder sparkplugs!"