There isn’t much room under the front cover on a Zephyr or Light Four for clearance so you will want to run shorty spark plugs if you are going to use boots on the terminals. NGK plugs, with a screw on terminal, in either BM6A or BM7A would be a good choice as they are of the correct thread size and heat range. The screw on terminal will also allow you to use the original ring terminals to, if desired.
In a pinch, you can make a ring terminal by using the wires core. Strip off a 1/2″ or so of insulation and split the core wire into two strands. These get twisted around a nail or something to make a loop which then gets soldered to hold it together. And excess then gets nipped off. This works good with NGK’s as they have a screw on terminal. Champions don’t.
