Man, that looks familiar.
NAPA used to make some stuff called Balkamp Battery Cable and Ignition Wire Sealer.
Basically it was just clear acrylic enamel.
I would buy a few cans every year. My Jeep, my father's car, all got a thick coating on all the spark plug wires, boots, coil and cap.
After it dried, we would crank the car and spray the engine hard with a water hose. If it skipped or sputtered, we dried it and resprayed.
On my Jeep, the warning point was my navel. After the fan and headlights went under, I could keep going until my navel got wet.
At that point, I had to make a decision, because it was close to the top of the carb.
During the course of a hunting season, I might cross a creek or small river up to my crotch 4 or 5 times per day.
Not sure why I never had problem with water in the engine, but the front and rear ends filled up along with the transmission and transfer case.
Never had any damage as long as I kept the gears moving and kept the stuff stirred up. If it sat up any length of time, the parts out of the mix would try to rust.
End of hunting season, I would drain everything. Always got nice clean water then oil out if it had been sitting up long enough for the water to settle out.
I found out that that does not work with automatic transmissions. When water gets in them, it soaks into the brake and clutch bands and causes the lining to delaminate.
Going into my camp, the big river often comes up and floods across the main road. I know the limits of my truck, and don't try it when it gets above that.
But, some of the folks that live down there can go through when its deeper than that.
They mount a sheet of plywood from above the front bumper sloping down towards the back about down to the level of the front axle.
Then, as long as they keep moving, it pushes the water forward and away creating a low spot behind the wood.
I never had the nerve to try it, but I have seen them go through some awfully deep water.
Of course, they keep the doors open slightly and some weight in the back to make sure it does not float off.
But, if they ever stop, its gonna fill the engine........