On each cylinder head there are 2 bolt holes (one in back and front) that threat into coolant passages. The coolant crossover tube threads into the back but what threads into the front holes (behind the accessory bracket and ignition coil). Are they just blocked off with bolts or does something else go there. Thanks in advance

 

The front holes are plugged off with pipe plugs.

 

What about the hole on the side of the passanger side head (where the temp gauge sensor would be on the driver side head)

 

Both heads are identical, so one side has a plug, the other has the sensor.

 

Thanks I appreciate it