5.5 head

[Dodge]

Just a side note. Don't use a tap to clean up the head stud holes. Use a thread chaser.
The thread chaser will clean out the threads. The tap will cut material out of the stud holes.
There are three grades of taps. Each one has a different tolerance of depth cutting.
The taps most of get from the hardware store, Snap-on, Matco ect. cut a deeper thread
than the taps that are used in engine manufacturing.