Dan,
Currently crossing the Atlantic by boat. Wil text photos when I can move more data. The more I look at you car the more I would be inclined to leave it alone. For a 280 that is a really clean engine compartment that is original and the car just may be worth more the way it is. A couple things like clamps, spark plug wires, distributor cover etc need to be remedied but small stuff overall. You might want to source a metal coolant overflow bottle since there are very few plastic ones available and you might want to take it off and preserve it in case you do show the car as original. As an aside SAVE EVERYTHING that comes off the car. So many times during restoration or repair hard to find items are tossed away.