Two additional passages (small water holes - for coolant) between the block and the head are needed for each pair of "siamesed" cylinder bores - six additional holes in total (in comparison to the 235 head/block).

The two small holes are shown below for one (of three) pairs of cylinders. The holes in question are the two smallest diameter holes in-between the cylinder openings in the head gasket.

Tim

[img]http://ares.cs.siena.edu/~lederman/truck/Photos/261headgasket.jpg[/img]