It depends on what you are doing with the motor and your degree of patience with learning and tinkering. If it's NA and you aren't going to be constantly upgrading the A9 Ford computer with a chip should work. I would recommend just paying someone to burn a chip for you if that is your path. If you want to do nitrous or boost and you don't mind spending the money FAST would be be the best do it yourself option IMO. Not the bottom dollar FAST EZ EFI computers - those self-learn and you can't really tweak them much. Yes, an 80s-90s Ford ECU with an aftermarket chip added can allow you to adjust using Moates or other software, but from what I've read the learning curve is very steep. I spent some time looking into it. I'm an engineer, so I do like tech, but it seemed like a lot of reading, research and learning to me. More time and fussing than I would want to do. If you have the patience to spend months or possibly years learning the details of a program and tweaking things for driveability - definitely do the Moates. However, remember if you make a tuning mistake you could end up killing your engine. It could be an expensive mistake!
I'm building a 408 Cleveland that will be EFI. I'm just planning to have a local company burn a chip for me. I think it's $300-350 range. I'll use the A9 Ford ECU and the Ford EFI harness that's designed for adding the A9 ECU to a hot rod. One thing I don't love about the Ford EFI harness is I don't think the wires are long enough - they don't provide enough flexibility in where to mount the computer. I used the harness originally to convert an '83 Mustang to EFI, and it was tight to get the computer under the dash on the passenger kick panel. Using the A9 ECU with an aftermarket chip won't give me adjustability I can do myself, but my motor will be NA. I shouldn't need a lot of adjustability. The 80s Ford ECUs actually are pretty good at self-adjusting and handling changes to the motor like heads, cam etc. as long as it's nothing too crazy. If I really need to I can go back to the guy who burned the chip for me and have him do a new tune. Typically they will let you come back for adjustments as part of the original package deal. I don't think you can incorporate a knock sensor or pull timing under boost into the EEC IV models - so if you want those features the A9 ECUs are probably not right for you. Then I think you'll want to step up to FAST, which costs a lot more but will be a lot more flexible. If it were me I would just wire in the extra electrical parts yourself as part of a new wiring harness. Just buy a somewhat generic wiring harness from American Autowire or Painless that has enough capacity for the circuits you want. I think the American Autowire classic update models have the extra circuits but still fit our cars. I haven't gotten that far in my research yet.
I'm planning to use a carb intake and a Duraspark distributor when I break in the flat tappet cam, then put the inner valve springs back into the heads, install the EFI intake and wiring, tow the car to the tuner, and have him do the chip. My EFI distributor will be a modified part from a 460. If you go Ford you can use something from a 351W out of a 90s pickup, I believe. The tuner will do a couple re-burns to the programming as part of the deal. It's a lot of extra work to break in the cam - I wish I would have gone roller!
