distributor caps

Q: I have a 1976 Chevy Blazer with a 320 hp small block. It has a 600 cfm carburetor, MSD 6A ignition with an HEI adapter kit, and a heavy duty distributor cap and rotor. I keep melting a hole through the distributor cap, plus the center terminal (spring included) and the arc seal. I swapped

I was working on my engine the other day when I pulled the distributor cap and noticed what looked like grease around the inside of the cap. But what really caught my eye was the strange buildup of crud on one end of each spark plug wire terminal on the cap. What causes this and