Block structure for an internal combustion engine

An internal combustion engine comprising a cylinder block, a cylinder head, and a plurality of fasteners tightenable to apply a load to the head to hold the head onto the block, wherein the block comprises a single structure having:

• walls defining a plurality of bores arranged in a line for receiving pistons, said walls being arranged to receive part of said load from the head;
• and a support structure comprising transverse support sections extending across the block between the bores, the support structure further comprises longitudinal support sections extending along the block one on either side of the line of bores substantially tangentially to the bores which are joined to said walls so as to provide support for said bores, and the block includes joining regions where the longitudinal support sections are joined to the transverse support sections, and the fasteners include engaging means arranged to engage with the block such that a substantial part of the load received by the walls of the bores from the head is transmitted to the fasteners via the joining regions.