Great, thanks for the info everyone. I'm not removing the engine to replace it, it's seized, so I'm going to try to crack the frozen piston(s) loose. I saw on youtube that some Europa pistons get so stuck in there that torches and sledge hammers can't bust them loose. The car also has 50k miles on it, and based on searching this website, it seems that most people rebuild their engines around 50-75k miles because the crankshaft/cam bearings wear out. I don't really want to remove the engine and would ideally like to crack the piston loose with more mystery oil, but I bought the car as a project, and project cars always have unexpected turns in the road to restoration. Most things I can repair/inspect/replace while the engine's in the car (head, manifolds, oil/filter, most gaskets, water pump, belts, alternator, starter, oil pan gasket, oil pump, distributor, worn motor mounts, etc.) But I wanted to take the engine out to replace the timing chain/gears/guides/tensioners, cam bearings, crankshaft bearings, piston bearings, piston rings, cylinder base gaskets, etc.). When I bought the car a few weeks ago the cylinders already had mystery oil in them to soak but it's still seized. Someone on this forum said to try Coca Cola in the cylinders but it's 16 degrees here in upstate New York and freezing liquid in the engine block would cause more havoc.