Join Date: Jan 2019
Location: Sedgwick, Kansas
Going with EFI presents a lot of challenges. There will be a lot more wiring, and you'll be running new high pressure fuel lines. You'll probably want to run an EFI fuel tank too, with baffles to prevent starvation.
The Ford style fuel injection requires either a cable-style pedal (which I hated on my '67) or you can turn the upper plenum around 'backwards' so the air intake is on the right. That will let you use the stock linkage, but will require more wiring. On the plus side, you don't have to move the battery, once the air intake is on the driver's side.
The biggest drawback to the stock 'flop hat' Ford injection system is that you can't run a normal export brace. It just won't clear. For that reason if no other, you'd be much better with a carburetor style intake.
If you do go with a carb-type intake, then you need to decide whether you want to go carbureted or fuel-injected with a carb-type throttle body. Holley Sniper is my personal favorite, but the Atomic EFI system and FiTech can work well too. You can't be too careful in wiring them so they get a clean power supply. Don't forget, you'll still need to deal with a high-pressure pump, special tank, and fuel plumbing if you go that route.
EFI systems should use a single-plane manifold. They don't suffer from the same problems a carb does at low RPMs, but they will have problems with a dual-plane manifold. It's my understanding that the EFI gets confused about pulse timing from side-to-side with the two separate planes, and this causes all manner of idle and tuning problems, along with stumbling.
For a carbed system, you're better off with a good dual-plane like an Edelbrock Air-Gap, or Weiand Stealth. I really like Summit's M-series carbs, which are essentially based on the old Autolite 4100, but with some other nice features. Inexpensive, but excellent.
If you want a 4 speed automatic, the AOD will work, but in stock form, the shift quality is mediocre, and they are prone to burning up friction materials or shearing their lockup torque converter shaft if you make full throttle 2-3 and 3-4 shifts. IMHO, you are much better off going with a 4R70W transmission, and spending the money for a Baumann controller. It's essentially an updated version of the AOD with stronger parts, using electronics to shift instead of hydraulic circuits. Shift quality is much improved, and even in stock form, they can handle far more power than a stock-block 5.0 can deliver.
While it's possible to make an AOD into a decent transmission, you generally have to give up the lockup torque converter features and go to a 1-piece input shaft, as well as adding some of the upgraded features from its descendant, the 4R70W. By the time you put in the money and effort to do all of that, you might as well have started with the better transmission anyway.
Both the AOD and the 4R70W require a different transmission mount, and probably some exhaust and driveshaft work as well.
I am also fond of the good old C4 automatic. They're lightweight, shift great, and they're tough. But of course, you have only three gears, so there are some compromises. I run mine with 2.80 rear gears, which hurts my acceleration from a dead stop, but makes it a joy once she's rolling. Because my drive shaft spins slower, I also have a lot less driveline vibration. If you put in steeper rear gears, you can have all the fun and tire smoke you want, but your highway RPMs will increase proportionately.