Water passage in head

[Karl]

This is probably a dumb question but if you look at the head there is a large banana shaped opening in the center of the head at the edge above where the water outlet on the block is. This doesn't correspond to any water passage in the block . So the opening just rests against unbroken head gasket. Is there any point in having this opening there ???

 

[Larry Brumfield]

Yes, it provides an area of support and alignment for the core (water jacket) as do all the cast water openings when making or assembling the mold for the head. I'm not sure if some early blocks had the same opening and used it for water or not.