Exactly what I was going to say. I cannot post a picture of why it won't fit because I didn't take one when I was working on my setup but I can tell you from EXPERIENCE that I wasn't able to install it. It's been a while since then but if I remember correctly the slot didn't align.good info.
how did you confirm that the b7/a6 tensioner can be "swapped" with the z6 one? In my recent experience the z6 tensioner did not fit the zc/a6 block.
EDIT: Found these pics online (amazing what searching can do!)
From the thread I had found, it states the Z6 and Z1 share the same tensioner and the D15B VTEC is nearly the same EXCEPT the roller is smaller in diameter. Bottom tensioner is the B2/7/A6.
Comparison between the Z1/6 tensioner and JDM D15B VTEC tensioner.
Also, the thread stated the same thing, B2/7/A6 tensioner is not interchangable with the Z1/Z6 tensioner.