Are the autolite 3923's hot enough to run 20psi on? I know I'm still having fuel problems with it running rich, but I will be getting it tuned one week from today. Everytime I check my plugs they are black from fuel. They're not as bad as they used to be, but these plugs don't have but three hundred miles on them and they're black as a boot. I was just wondering if they are burning hot enough. That may not be the right terminology, but hopefully you get my meaning. Thanks, Jay