A number of things can cause overheating, plugged radiator or coolant lines, weak water pump, non funtioning water pump, ( look for coolant coming out of the weep hole on the upper side of the pump) incorrect timing ( too far off advanced or retarded especially, can cause overheating.) You mentioned having an electric fan, that's not a stock item. I'm believe Trackicks came with a clutch operated fan, driven off the water pump pully. Check the simple things first, belt tension to the water pump being one. A non-functioning fan will cause overheating in slow going, but at highway speeds there's enough air moving through the radiator to not need a fan. I replaced my clutch fan with a switchable electric fan so I could turn it off during deep water crossings. I don't even use it ( the fan) on the highway, and it's off most of the time in town as well. Start by checking your timing. Specs are located on a tag under the hood, or in the FSM.