I'm swapping a d15b2 head onto an a6 bottom end(the a6 head is toast), and I'm wondering do I have to mill the head or block? They're both flat, I did a quick straight edge check, but I'm going to be running 7-10 psi through it later on and I don't want to blow a gasket.

 

take your choice. mill or deck, either way you'll be and feel better doing it. then you'll know its flat. id suggest milling, just cause you dont have to bring in your block. good luck.

 

what's the difference between the two?(milling decking)

I'm just gonna slap them together and see if it holds, I'm only shooting for 7psi anyway and they both look pretty flat with a straightedge.

 

One of those "import magizines" said that something like 80% of d-series block surfaces are not flat b/c the center two cylinder tend to drop down a little, but that's not from personal experence.

The article was the recent "buget boost" part 1.
I'm thinking it was "honda tuner".