Most Certainly a Head Gasket But......

I get a phuft, phuft, phuft while the engine is running. The noise is coming from the junction of the head gasket and engine block right at the back of the engine in the middle facing the firewall. One phuft for every stroke of cylinder 4. I can feel the gas escape and the engine block seems to have a rough patch exactly where the gas is escaping.
Before it goes for a head gasket could I be looking at a cracked engine block (that rough patch) or has the escaping gas worn a rough groove?

Your thoughts appreciated.

Classic place for the gasket to go, don't keep running it or it will groove the head and need a skim.
Block will be ok I bet.

What he said. Get the head off sooner rather than later. It's not a difficult job at all.