My car is Missing

Hey guys its not what ya think. My car is here with me. The problem I have is just yesterday my car was running fine and it has been for about 150 miles since I brought her out of the garage back in late April. Well I was crusing down the highway and I noticed that my car seem to be acting sluggish. It has aquired a slight miss and seems like its running on 7 cyl. With the 508 purple cam it seems to idle ok and starts up and shuts down fine. It only misses when you accerlate.Thought I may have a fouled plug. I had just this winter put new plugs in so I pulled all the plugs and they were all fine,even the resistors were white. I double check the gap and all were at .045 right where I had gapped them. My spark plug wires look to be in good shape. I examined every one and two of them have a slight rub mark from my valve cover and one from my throttle linkage on them but I dont see ark jump which I checked at night time in a dark garage These wires have been on the car for 4 1/2 years. I have checked the "D" cap yet. The cap and rotor was new 2 yrs ago along with the Blaster SS Coil. So my question is, before I start tearing into things, even though wires look good could there be a break down in the wires from all the heat that I cant visually see or feel? I am running 340 c.i. .030 over with MSD 6A, Headers, and I know the wires get a lot of heat. Can the Blaster Coil be causing this problem? Or how about the rotor / cap? Previously it had a tan cap but this one is black. Any difference between the colors? A friend of mine is leaning towards the spark wires being weak. What do you guys think the problem may be? Any feedback would be greatly appreciated.... Thanx