What spark plug wires should I use with a Vertex mag?

[Sam K]

I just took my car for a test drive after installing my magneto today and it didn't go so well. It pops out of the carbs and misses and backfires under load. It acts like one of the wires is bad and they do look a little old. What do you guys reccomend for replacements?

[JS]

I run stock Bosch with no problem, though Ive heard some people say you should run wires without resistors at the end.

[Matty c]

Copper core, no resistors 

[Lanny Hussey]

If the engine runs OK after startup, then gradually worsens, the mag needs a service.

[Fastbrit]

If the engine runs OK after startup, then gradually worsens, the mag needs a service.

X2. The man speaks wise words (obviously not beer time yet!)...

[hotrodsurplus]

Check a few other things first.

The numbers on the cap refer to the magneto firing order ONLY and NOT cylinder firing order. So if you set it so cap #1 corresponded to cylinder #1 then cap #2 would correspond to cylinder #4; cap #3 would correspond to cylinder #3; and cap #4 would correspond to cylinder #2. My dollar says that's your problem.

Mags typically don't tolerate (or need) big spark-plug gaps. The big gaps that CD ignitions tolerate tend to work poorly with inductive sparks. Try .015" to .020" plug gap as a baseline.

The magnets could need energizing.
The points could be set at a figure other than .015".  

Copper-core wires and non-resistor ends (black if using Bosch, not red) are necessary for best results.