Joel is being too nice to me today
The front of the 260Z is a bit different than the 240Z. Actually, the space between the frame rails is significantly less in the front where the intercooler mounts. Although this core fit easily on my car there is some small clearance issues on the later 260Z. Not a big deal at all. The core was sent back to me and will be modded promptly with a new tank design based on the dimensions of the 260Z. I have to admit, this damn core is very impressive and for $650 I don't think you can beat the performance. Will keep you updated. BTW, there are no issues with hood clearance once the intercooler is lowered to the correct height.
Here is a drawing of how the tanks are to be modified.