I've been struggling with fouling spark plugs for some time now. I've gone with leaner jets, lower numbered power valves, different carburetor, all to no avail. I think that I need a hotter spark plug but I'm not sure which ones I should buy. I'm looking for something cheap. Right now I'm running Delco Rapidfire #5s. Any help would be greatly appreciated.

 

are yuo sure the ignition system is in good shape? that may be your problem. is it oil or gas causing the problem? step up one or two on the heat range with plain jane ac plugs and see how that goes.

 

This is interesting...

I went to Advanced Auto and told the guy I was running Delco Rapidfire #5s and was looking to get a plug that was two heat ranges hotter. He looked up the part numbers and said that they didn't have it. So a little later in the day I drove down to O'Riley's and told them the same thing. The response I got there was "They don't make them any hotter than a #5". So, people knowlegable about spark plugs...is there anything hotter than a #5? What's the part number on it? I don't care anything about staying with Rapidfires, actually, the cheaper the better. Any help appreciated.