Those Sparkplug screw plugs are bakelite and break easily. This makes them hard to replace. Finger tight only. The plug wires are taped up because the insulation on them is rotten. There could also be a break in one wire which would give you an open reading. The plug wires at the coil are surround by the black gunk. They are junk and need to be replaced no matter what. Good or bad the coil has to come out. Then you can test the coil, at the coil. A heat gun will soften the tar. These coils are rarely bad but a used replacement shouldn’t be hard to find if you do need one. Modifying a later coil may also be possible.
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.
