Question on head gasket and oil additive

55 Chevy · 01-21-2009, 12:37 PM

The bore size on a new # 3995633 is 3.980. This gasket was used for the 307 motor,is steel shim & has a coating on it.
As far as I know G.M. has discontinued this gasket.
Not sure of the Fel Pro cross over #.

There are a couple of smaller bore gaskets G.M. # 14085906@ 3.875 & # 462690@ 3.875. They are both steel shim & have no coating on them.Also no longer available.

Just curious,what is the exact bore size of your motor?

Allan

01-21-2009, 12:37 PM	#7
55 Chevy Member Join Date: Feb 2008 Location: Calgary,Alberta area Posts: 229 Likes: 23 Liked 20 Times in 15 Posts	Re: Question on head gasket and oil additive The bore size on a new # 3995633 is 3.980. This gasket was used for the 307 motor,is steel shim & has a coating on it. As far as I know G.M. has discontinued this gasket. Not sure of the Fel Pro cross over #. There are a couple of smaller bore gaskets G.M. # 14085906@ 3.875 & # 462690@ 3.875. They are both steel shim & have no coating on them.Also no longer available. Just curious,what is the exact bore size of your motor? Allan