Why not just run a second Ford IAT and put a switch between the two? You could run relays to enable each circuit if you're worried about extending the wring or increasing the resistance by running wire to a cockpit switch. That way you keep your datalogging abilities and can quickly gain back to back runs to log before cooler and after cooler temps.
Run off of the "hot IAT" (the one before the cooler) and it would pull timing out for day to day driving, run off of the cooler one and the ECU would bump timing automatically for a day at the track.
