No cracks, never been repaired. They came off an old vintage flat bottom boat.
They look like they're magnesium, cool patina, but they are aluminum. The item "VINTAGE MICKEY THOMPSON 429 460 FORD HARDIN MARINE VALVE COVERS FLAT BOTTOM BOAT" is in sale since Friday, January 08, 2016.This item is in the category "eBay Motors\Parts & Accessories\Boat Parts\Inboard Engines & Components\Other". The seller is "projectmikes" and is located in Bonsall, California. This item can be shipped to United States, to all countries in Europe, to Canada, to Australia.