I thought about doing this along time ago, but after I talked to Ford Motorsport, they told me that the EEC IV was designed to and would run better with the alternator voltage (13.5-14.5 volts) instead of the battery voltage(11.5-12.5)
I never actually tried it but, I do know one time my alt went out on a short trip and I only had about 5 more miles to get home so I went a head and drove it. By the time I got there the car was not running very well on what I had left in the battery, so I took that to heart and never did it?