Do you have blue smoke out the pipes (especially when it's cold!) or any other indicators that the valve guides or seals are bad? Do you know if the heads were purchased ready to run and bolted on or were they purchased bare and assembled by an experience builder who checked guide to stem clearance, did a proper valve job, checked and equalized the spring pressures and set the springs to the proper installed height? If I see a relatively fresh build and it's burning enough oil to make the plugs look like that, I would have already pulled the heads off to see what was happening. But it sounds like you have a reason to change the fuel tank and other parts of the fuel system besides them being 12 years old that you may not have mentioned. Is it fouling fuel filters? Is it possibly gacked out to the point of having stuck the floats open? If your not seeing any major signs of oil consumption, then I would go ahead and go through the fuel system before doing anything else. Also, what brand and what number of spark plugs? It looks like you have an MSD distributor and a blaster 2 coil, are you running an ignition box with that? MSD recommends .050 of plug gap with a 6AL or Digital 6 box now.
