"Years ago I worked at a marin
"Years ago I worked at a marina on Lake Murray in SC, and we worked on "salt water" boats fairly regularly. I remember trying to get a very stubborn distributor out of a Mercruiser 260HP V8 (GM 350 cid). Soaked it for days with WD40 and applied heat, even tried trying to force the base to rotate by using a chisel & hammer. I finally notified the boat owner that any further attempts to remove the distributor would likely destroy the distributor and asked him if he wanted me to proceed, but I couldn't be responsible for damage to the distributor. He agreed. What we finally had to do to remove the distributor was to attach a chain around it and lift it straight up with our very large heavy lift forklift. The forklift lifted the entire weight (6,000 lbs.) of this 27 ft. boat up off the trailer. The boat was literally hanging by the distributor about 3 inches above the trailer when with heat and a hammer, it finally broke loose.
We installed a new distributor, and gave the old stubborn corroded (and slightly bent and dented) distributor to the owner so he could throw it on his neighbor's roof.
This problem can probably be prevented by regular seasonal applications of a good corrosion inhibitor, and more often if you're a salt water boater."