Re: 1954 359 L8 / Iridium spark plug in place of Autolite copper resistor 308 spark plug

Posted by HH56 On 2022/3/28 15:40:04

Others can better speak to any benefits of the various materials but one question I would have on the larger gap is if a stock 6v ignition coil would have enough spark to reliably jump such a large gap.

Many 6v coils have issues even with the smaller gaps particularly when the starter pulls heavy current turning the large engine and drops the available voltage. I would think the larger gaps would be more in tune with modern 12v coils that produce 40-50k or more and should be avoided in cars in the 25-30k range produced by a standard 6v coil.

Not only is the 359 a huge engine to turn with voltage drop to be expected but the higher compression also makes for a more dense atmosphere for the spark to try and jump thru.