The C4 is not electronic in any way.  It uses engine vaccuum, torque load, RPM, the shift linkage, and a kickdown switch (only active at wide open throttle) to decide when to shift.  I think that you can set them up for an electronic speedo with the right parts (i.e. electric sender unit) but it doesn't use any circuitry for shifting.

AFAIK, all ford smallblocks except for the early 5-bolt setup should work fine with the C4.  Shifter linkage can vary a bit though - some have levers that hang down, some go up, etc, so you might have to hunt some small parts, or take loose a nut on the shift linkage and flip the bar over as needed.

If you're really going to have to do a lot of fuss to make the c4 work in your car, I would strongly recommend going to one of the newer 4 speed automatics like a 4r70w.  I've always been a huge fan of the c4, but that overdrive is hard to beat, and you can make them perform pretty well.

yes the guy who is selling it has a souped up mustang 91 with 4.30 gears and went with a 4 speed instead of this tranny