FMX to 4R70W

That's a near complete list of possible parts and issues.

The 4R70W got the last major upgrade in the 1998 model, the mechanical diode. But that you can buy separately if needed, and the same for almost any other components. It's a very well supported trans, though it is waning in availability now that the last were made in 2004. But any SBF bell housing model from 1998 to 2004 will work fine. The biggest key is the past care, mileage, and what prior issues it may have had. That's why a lower mileage unit is worth much more, if possible aim for one you can trust has not had any big issues.

The trans cable is an interesting issue, I'm not sure how that will connect to the existing car shifter, column or floor. The trans side is easy if the 4R cables are used.

There's only one controller to buy, aside from the built in high dollar EFI systems from Pro M and Holley. From what I read, the Quick Shift 4 is well designed, easy to wire up, and user friendly to tune yourself. I need one of those for both of my Ranchero's, I'll be using OEM computers for my Mark VII and Explorers, which are cheaper that the Holley EFI in the end.

Any of the early electric speedometer cars will use the needed VSS, speed sensor. Among the earliest will be a Ford that had a mechanical cable, which went into the VSS at the trans. There is a need because of that for a model with the sensor back there, which ended in the 2000 range(earlier for some car models, later for others). That just means you will need an output shaft that has the speedometer splines in it. That can be had separately too of course. I have a 97 Explorer 2WD 4R that I plan to use for those odd items, the output shaft and rear housing(2WD). You can use a 4WD trans but the rear output shaft and housing would have to be swapped of course.

Any automatic needs a good cooler, the best are those from Super Duty Ford trucks, which came in various shapes and sizes. I like the type which are fairly narrow, and longer, to run side to side near the bottom of the radiator. Most non heavy duty Fords came with a cooler that's about half the volume it should be, same for all aftermarket coolers. That's why the Super Duty coolers are better, they are normally double a typical sizes, or more. More is better always for trans cooling.

The 4R70W's that will bolt easily to the SBF all have two starter bolts, that's the easy visual test. After 1998 the only note worthy change was to the planetary, the big rivets became a kind of spot weld, but that only affect power way higher than a typical SBF.

Try to find a TPS that adapts to the carb you have, avoid Lokar cables unless you cannot get an OEM cable to work well. The OEM cables are more reliable at the end connections.