We understand how one may be confused when comparing prices between marine and auto parts. They are vastedly different, despite their outward similar appearance.
The most important factor to remember is they DO NOT cross over. Never install automotive parts into your vessel, the results can be DEADLY!
The prices are different because the marine specific sealer and internal parts are made of different materials. Brass vs. aluminum and silicone vs.3M 5200 and so on.
Automobile engines are designed to ventilate airflow and have open engine compartments, unlike a boat. If this is a suprise to you, you may need to take a terrific coarse provided by the Power Squad or Coast Guard.
What you don't know can kill you.
Boat Safe, use only marine certified parts.
Bestest,
Olympic Marine Crew Team