Thanks for your replies. Its hard I guess without pics, but I will post some later tonight. The damage is to the surface which mates with the head gasket. One of the corners of the top of the short-block (where you can see the pistons at the end of the cylinders) has taken some sort of impact on the corner.
As a result, the alum. is 'pushed' in about 2/3mm and the top surface, which the head gasket sits on, is no longer totally flat. Think of what happens to your hood if you read end a car!
Its not protruding much, but possibly by 1/2mm. It is possible to get the top planed to remove this 'bump'? There are no visable cracks anywhere, but I will see if I can find someone who can carry out some sort of thermal scan of the block to check it.
thanks for your replies, I will post in here when the pics are up in the Pics/vids section.
