While I don't have the FAST system EFI, I did install the Holley EFI system. I would have sold my Pantera without it. The idea of just turning the key to have the engine erupt into the joyous sound of it running was completely foreign to me. My pre-EFI procedure was.
1) Attempt to start by turning key (never started)
2) Pull the air cleaner
3) Dump fuel into the carb
4) Run back into the car hoping it was still running long enough to squeeze in and rev a bit
5) Run back out screw the air cleaner back on (and hope it was still running
6) Attempt to drive away, sometimes successfully, ofttimes not successfully and restart the same procedure.
I hated the thought of starting the car, so I never drove it. My Jag XKR was quicker, more comfortable, reliable, and NEVER FAILED TO START, so I gave up driving the Pantera. I seriously thought about selling but couldn't bear to do it. So, I made the choice to make it a more user friendly experience starting with EFI and ending with redoing much of the car. I still have some issues which we're working on but at least I save about 20 minutes of grief every time I start it. Anyone who hasn't considered EFI and is not concerned with absolute originality, should certainly think about it. You'll wonder why you hadn't done it years earlier.