This thread is funny, I think it boils down to are you trying to build a bmw or a old muscle car?. I for one don't spend all the time and money I do to hop in what is essentially a modern car and cruise/hit the strip, why not buy a later mustang and go faster more efficiently cheaper and with less hassle.
I think for those that want a kindig it car fine but all the pro efi arguments made here pertain to gas mileage and cold start/drivability etc., things that are meaningless in my vintage muscle muscle machine. Again if you want that fine but you are starting out on a more costly time consuming path that would be much simpler if you just bought a modern car, I mean rear window defrost and delayed wipers sure are nice for those cold wet mornings.
It would be one thing if someone could legitimately show me a back to back dyno test where efi will make more power than a carb and greatly improve my overall performance/reliably but they cannot. It simply isn't true, all the benefits of efi are related to convenience, longevity etc., but even that's with factory engineered reliable parts (jurys still out on aftermarket kits).
I would think that most enthusiasts in this hobby would agree with these basic statements.
I'm not looking for 100k + miles out of my rod
I don't care about driving away in 20 degree weather in ten seconds.
I'm not looking for the added expense/complexity of efi on my old car, and certainly don't want to try to repair it on the side of the road.
If that's what you want to do with an old car more power to you and I appreciate that, but to come on a old car forum and say efi is a definite upgrade for an older car is just an opinion. For what most of us are trying to achieve efi is not a worth while investment for a weekend machine and will not give my muscle car more performance over a properly done carb in the conditions I drive on the street or track. For that matter it would actually take away from the raw simplicity/ performance I have come to enjoy.
