"Block relief" - L.M. Williams book

[Stuart Giles]

Well worth relieving the block on any sidevalve motor IMO. Some manufacturer's motors, e.g. late Ford V8 came from the factory with the block relieved. On an A7 motor I mark the block around the inside of the head gasket fire ring and that's the extent of the relief. It ends up looking just like the photo posted up by Terry -going too far down the bore would expose the top piston ring to excessive heat on the firing stroke.