Do you still have the original wingnut for the carb? I've had trouble with the stupid horseshoe connector on the coil (I cut the ends off and wired it direct with an '81 Dodge coil which ran MUCH better due to higher voltage)
Do you have a ground wire from the body to the motor/battery? If it broke off, these issues will happen (module overheats due to lack of voltage)

Build your truck the head men say, but it must be built in such a way...