I just had a 455 rebuilt and I have a large amount of water getting into the oil. It only ran for 2 minutes and the oil looks like milk. I upgraded the stock heads to the Edelbrock heads and Edelbrock intake. I did buy a new timing chain cover, but it visually looked the same. What did I miss? I pressure tested the cooling system at 15 pounds and lost 5 pounds pressure in 5 minutes. Has this happened to anyone before? Where should I check first? Is there a gasket in wrong? I have a bore scope I can use. Also, once I fix this, what's a good way to clean the engine now that it has water and oil throughout? Is just a few quick oil changes enough?