Quote:

Those big holes are sized that way to get the sand out of the casting in the foundry. This is true of both the block and the heads as they are "sand castings". The gasket reduces them to what they should be for cooling. I never tried opening them all up to the casting size to see what would happen.



I agree with this but the fly in the ointment is that around 1973 they changed the holes in the block to a figure 8 shape which ends up having a round hole right in line with the round hole in the head, BUT they changed the gasket from the rectangle to a slit.