Got a 64 327 in my 36, hei ignition, never has had an issue with anything to do with it. I just fixed a huge vaccum leak, (power booster), but still get an intermittent not runs quite right sometimes, stumbles a bit under acceleration, sometimes idles rough, but generally runs really well. New plugs less than a thousand miles, inside of cap looks clean and nice, rotor looks good, so, I'm leaning to plug wires which are, say....15 years old? I have replaced three, the header boots went all soft, and that cured an obvious misfire, but this intermittent thing is making me crazy, no vaccum leaks, carb is good (edelbrock), runs mostly like a hot damn, what is the collective opinion here? Mileage wise, they may have thirty thousand on them, they are high performance aurora wires, still got the box with spares. So....I ordered a new set, just looking for opinions, how long can a guy expect to get out of a set of wires?