A stock 65mm t-body bolted on a 2.5 Duratec is not really a good idea for a no. of reasons. The main reason is that it's simply not an apples to apples mod. Although the flange is the same, there are notable differences which preclude it from working properly.
First, the cable fulcrum is different-which means that XX amount of movement in the cable will not translate to the correct amount of rotation at the TPS. This means the PCM will be getting incorrect info. Next problem is that the Mustang uses a helper spring external from the t-body while the SVT t-body has a double return spring integral to the shaft/fulcrum assembly. The cable approaches from the top, not the bottom of the fulcrum, the air bleed hole in the plate is larger and then there's the sealing problems at the top of the SVT UIM. Plus, there's no built in shaft/plate stop like the SVT t-body.
Now a no. of these issues can be overcome reasonably easily, but others are not so simple. I HAVE gotten a 65mm to operate properly on a 3.0, but it meant combining parts of a 60mm (fulcrum & springs) with a 65mm (casting, plate, & shaft), a custom fabricated adjustable throttle stop and custom stamped gaskets. As you can imagine, there was plenty of custom machining and fitting to do to make it work properly, but it does work.
Now on a 2.5... I would have to see back to back dyno results to prove it's worth, if there is any. I know that the custom overbored 62mm certainly "woke up" my sorta' stock 2.5. An optimized 60mm is certainly a cost effective and worthwhile mod.
