Hey Guys,

How much does the millimeter sizing in plug wires come into play? Summit's webpage has a bunch of plug wires for a 5.7L 350 in a 1970 Olds Cutlass Supreme to be 10mm but there's a set of 8mm's on the car currently. Wanted to upgrade to a nicer wire loom set as well but most of them are for 7-8mm so I was concerned that I'm not running the right size or if it really matters.

 

It's not the size but the quality that matters. Where have I heard that before?.
You need wires that will deal with the voltage going through them. If you have a stock setup wires that meet oem standards will be fine, If you have upgraded your ignition system you will need wires to suit.
Of course you want wires that look good, but make sure they can deal with your ignition requirements first.


Roger.

 

Fat wires won't fit in the stock loom clips, and are likely to offer no advantage over good quality original-size wires.

Unless you're racing or have a very high performance motor, any spark plug wire will deliver enough juice to the plugs to make them fire, and any good spark plug wire will keep that juice inside the wire long enough for it to get there.

- Eric