Hello I have a 1967 F600 bucket truck. My engine is now on it's way out. I don't know much about the Ford truck engines. When I bought the truck I was told it had a 330 in it. A mechanic told me the other day it had a 391 in it. How do I tell the difference? Does both engines use the same bellhousing? What other engines will interchange with a 391 or a 330's bellhousing? Any help would be appreciated. Bill