Your life will be simpler if you go with an aftermarket PCM such as an AEM Infinity, as opposed to attempting to frankenstein the factory 3.7 PCM into operation. Factory PCMs look for a lot of data before giving the OK to so much as start the engine, and a lot of that data will not exist on your computer system. You will be bravely blazing the trail though, as I am not converting until at least next season, and I see zero evidence that anyone else is attempting this (granted this community is much less connected than the V8 guys).
2014 Mustang V6-Built to run TTB, CAM-C, and ESP
Proving to my fellow racers that the disdain that some GT drivers have for V6 drivers is unfounded, one results archive at a time since 2013.