Why would you want to use the 2.5 heads on a 3.0 if you are keeping the engine in a Taurus?
It would make more sense to put the SVT cams into your Taurus heads. You only need to cut off the extension that drives the water pump on the 2.5.
This will give you the larger 3.0 valves without the expense of changing them over. The compression is the same as the SVT. You can still port the heads for even better flow if you feel the need.
Just another idea.
