i had a problem the other day when replacing my head gaskets, it said in frpp's sidenotes that i may need to modify the head gasket in order for the coolant to flow properly. in my infinate wisdom i tore into a set of a302 frpp head gaskets with a file and a dremel to match the gasket to the block and head. but new news to me when i talked to a good engine builder buddy of mine today he said i needed to leave them there, even if it was blocking flow. so i talked to another good friend of mine who got in touch with some engineers over at ford. the reason behind the blocked pasages was for proper coolant distribution to the entire engine. certain parts of the gasket only have small passages to let pressure build in the engine so that the coolant goes where it needs to and not so "free flow". so $80 dollers later i learned my lesson by experience and am passing it on to the rest of the community. enjoy - james