I recently replaced all gaskets, timing chain and water pump on my coronets 318. I also cleaned out the water jacket and replaced all expansion plugs. Prior to doing the work the engine ran/idled great. Now that I put it all together and installed the new ceramic coated hooker headers, the engine is exhausting white smoke from the headers. I have only run the engine for about 5 minute increments for a total of about 6 times. Is this a common occurrence when doing this much work on an engine and should go away after a while?