I wanted more airflow for my engine with all the upgrades already done and I have some performance camshaft's ready to go in as well so a bigger throttle body was a must. My 4.7 now a 5.0 had a 65mm throttle body but it only had a 62mm opening. I got my hands on a 68mm throttle body of a later model that had a opening of 65mm. I had that machined to 70mm all the way through. The result was impressive and when I install the performance camshaft's one that was needed. You can buy these already made but they cost a lot more. I have also had feedback that the aftermarket throttle bodies don't work as well with the onboard computers. As my throttle body is the factory unit it connects perfectly.
Step 1: In This Clip I Install the Performance Throttle Body.
If you want to make your own performance throttle body there is a series of clips on my YouTube channel on how to do this.
Or I can do it for you as an exchange unit plus postage. But if your handy it is not a difficult job to do.