Partition plate for an intake port of an internal combustion engine, sand core, cylinder head and its casting method

A partition plate (tumble plate) for an intake port is previously placed in an intake port molding sand core (port core) for forming an intake port of a cylinder head, and cast-in as the cylinder head is cast-molded, to partition the intake port into a plurality of ports. The partition plate is provided with shift preventing portion that prevent positional shift relative to the intake port molding sand core.