You could get hood locks on any car but a 6 cylinder. Hood locks and black or argent paint was $18.00 option in the U.S.. Of course you had to spring for the NASA hood or order the Q code in 72 & 73 to get the NASA hood for free. Most electrical issues are related to grounds usually. Go get you a tube of Electrical Grease. Start taking the ground wires loose clean with wire brush, steel wool, scotch brite or such and apply the grease. Clean the light sockets and all connectors and bulbs and add the grease. If you have a boat trailer or camper you have to use the grease. Low miles or Kilos does not mean that wires and connections do not corrode.
You can test for blown head gasket they have a kit that checks for exhaust in the radiator uses a chemical that changes color.
The one I have is called Block Tester Part # BT-700 Google it.
There is also the possibility they put head gasket on backwards. Since a 351 W I think there is a core plug in the front end of the head. You can take the plug out and feel of the gasket inside. On the 221, 260, 289, 302, and 351 if you knock out the plug and feel inside there should not be any openings in the gasket should be closed. If there are two openings the gasket is backwards. Pic of typical gasket.
You sound like you are in panic mode. Just start fixing each issue one at a time and it will all work out. Do not try to fix everything at once. I would check the radiator for exhaust gas first. Some parts houses have the test kit and will rent or loan if you buy the chemicals.
If you just want to get rid of let me know I would be interested.
I was at a show this weekend and the was a 1965 Mexican Mustang there but I did not get pics. I poured the rain and I did not go outside, lol. One person that viewed said the door tag was in Spanish for sure.
In the gasket picture would be typical for the drivers side. The front is to the left and does not have the two holes like in the rear. The gaskets are clearly marked FRONT do not even look a log means nothing put FRONT to FRONT and good to go. Blown heads gasket is a Saturday fix.
