After an engine has been bored over at least .030" does a special head gasket have to be used? In other words do I need a .030",.040",.060" head gasket or is a head gasket a head gasket?

 

From what I can see the gaskets come with a bore size of 4.100", which allows for up to a .100" overbore. Here are some links to support that:

• Fel-Pro @ Summitracing
• Edelbrock @ O'Reilly's
• Fel-Pro @ Amazon

 

Can you say "porous cylinder walls"? [especially since I drive a 4.9L/300]

 

Most of the head gaskets come with a bore side of 4.100, but you can find them with bore sizes of 4.030, etc. Prices vary. Head gaskets also come in differing materials, too, depending on how much you want to spend and the application. Also, they can vary in thickness, which can affect compression ratios. Some cylinder heads aren't compatible with some gaskets, so double check that before committing, as well.

 

I think DW would call that "coolant failure" - the coolant failed to stay in its passage.