My '46 had the engine rebuilt by the PO shortly before his passing. It was painted the orange color too. The engine sat, never having been started for some 20 + years. I decided to use the blueish grey color engine paint too. Last fall I used acetone to remove all the orange paint to get to clean bare metal. Time will tell if my approach holds up. But, at least the orange color is gone. I applied two coats.