Re: Suggestions on Wires, Spark plugs, and gap settings

Posted by Owen_Dyneto On 2010/3/30 16:13:04

Kev, the 45 and 46 are so extremely close in heat range that you can consider them interchangeable 99.99% of the time. Depending on engine condition and how it's driven, sometimes a single heat range hotter or colder will be suggested by examination of the plugs after a 1000 miles or so of use. Since many collector cars see more low speed driving than they did when new, I prefer the slighter hotter plug.

Last time I shopped I couldn't find non-resistor plugs from AC so I switched to AutoLite 308 for the 51-54 Eights which is the same plug I use in 32-34 Eights and Super Eights. My own feeling though others may have different experiences is that resistor plugs perform just fine in these cars, but I wouldn't recommend using them in conjunction with resistor high tension wires.

EDIT - I just checked the recommendation in my 1962 AC catalog, it suggests AC46 for all 1951-53 and AC44 for all 1954. I'd still suggest, regardless of your first choice, driving the car for a while in what you expect will be it's typical mode of use, and then examining the plugs and using that as a reference for a final plug choice.