I have a 59 Invicta with the 401 nailhead. The freeze plug at the front of the left (as your sitting in the car) cylinder head is corroded and leaking coolant. Thankfully it is fairly accessible with the battery out. Can anyone give me advice on the best way to remove the old plug and install a new one? Someone suggested drilling a hole and using a slide hammer on it.
Or punching a hole (drain engine first) with an awl, then prying out with a screwdriver through the awl-hole. And of course, plenty of WD-40 soaked ahead of time.
