Here is a page from the Autolite spark plug website. You plug is in the red box. You can tell from the other brand plugs the relative heat range for your plug and where it falls in the overall hot-to-cold spectrum.
Before you start to make plug changes, I would encourage you to get your carburetor jetting, power valves, and whatnot squared away. Once you have the engine getting fueled properly, you can move your heat range around to suit your preferences. The plug you have right now should be pretty close to what you will want in the end.
Here is a pic that might help you to read your plugs. Street-driven plugs are never clean, but a proper heat range and proper engine fueling should produce a plug that looks like the plug on the left above the self-cleaning temperature line in the pic that says, "You want this look ..."
