I want a head that has not been surfaced before. I guess that that should be properly stated as one that has not been "resurfaced". The factory surfaces the head when they manufacture the head. Therefore, I want a head that still has the factory surfacing, and has not been machined since new.

There is a way to find that out.

The cylinder head thickness or "height" is measured between the deck and the cam cover machined surface. This image illustrates that procedure with a 6.000in dial indicator.

The height for a new head is: 146.1mm [which equals] 5.7519in

The minimum height after resurfacing: 145.6mm [which equals] 5.7322in

The metric specs given above are uniform in all my green manuals; but the conversions to inch in one green manual I have says that 146.1mm equals 5.756in....and that 145.6mm equals 5.737in.; while in all other green manuals I have 146.1mm equals 5.752in.....and 145.6mm equals 5.732in.

I'll trust the metric specs; and do the conversion to inch values myownself.

Taking the 146.1mm spec for a new head, I convert that to 5.7519in. That is the height I want to see on the head I am going to use.

[I actually did measure two heads that were 5.756in.....hmmmm...]

Taking that experience into consideration, I want to see at least 5.7519in for a height reading.

For all the head shaving enthusiasts I have a question: if shaving the head deck 60 thou is okay, then why does Volvo list a minimum height of 5.732in?

That indicates to me that Volvo says only 20 thou can be shaved off the head deck.

I think that I will use the Volvo minimum height as a rule to abide by, especially in light of what I have seen in brinelling, sinking, and headbolt area distortions.

The main reason I want to start with an unsurfaced head is because I want all the aluminum I can have in the deck. And starting with an unresurfaced head will give me that.