I've always been interested in adding an EFI system to a Flathead. I've started several,but unfortunately they didn't work very well, or the cost got out of hand and I couldn't afford to continue. The first one I tried worked like a charm, up to a point. Back in the late 80's I installed a system from a 4 cyl
Chrysler engine. I used the gas tank and just made an adapter to bolt the one barrel TB to the engine, Using one of my converted SBC distributors to trigger
the electronics. The engine started and ran great on my dyno. Torque readings were consistent with a carbonated engine. Unfortunately the electronics of the Chrysler system limited RPM to 3000, because it thought it was going 6000. I called Chrysler and asked them how to disable the rev lintier, but they wouldn't help. That information is now available. I think this system could be brought up to date and with a better TB run a stock engine quite well. This would be the least expensive of the lot. My present system is alittle more expensive, but offers a much better multi port system, and controls the ignition system as well. I;m sure it can be done for less than a 1000 bucks. Megasquirt offers a Kit for the 5.0 mustang that controls every thing. The cost is about $350. Next you need an intake manifold from a 302/351 for parts. (Sensors) and TB. This can be purchased forn a junk yard for very little cash (87/94) The hardest part is brazing the injector bungs to the intake I'm using a Merc. 4 bolt.
Then you have to program the fuel and ignition system from their web site.
You can also use a stock distributor converted to electronics as their is no advance. I have most of the "Stuff" hope to get it working after the roadster is done.