I have a 85 CJ7 also - I have a little less than 2 inches of clearance between the fan & radiator. You fan should be tucked into the fan shroud (assuming you have one). You may want to check the motor mounts - just to make sure one of them is not busted allowing the fan to 'move' into the radiator when the engine is under load (ie wheelin').
Would it be
It depends - there are trade offs. If you have an electrical prob - you lose your cooling as well. Does your Jeep run hot ? If not - don't worry about it. Probably the best is to have both. use the normal fan and then put a pusher fan on the front side of the radiator. You could hook it up to a toggle switch and turn it on only as needed.
When I replace the
Could not hurt the system to get flushed. If the coolant that was in there was in good shape (clear green and NO rust) I would not worry too much about it. If there is any discoloration - flush it. Depending on the climate you are in - you may want to consider making the radiator a 3 core. The typical stock radiator is a 2 core.