Hi there!
A 1994 should have a 42RH/44RH transmission, so the only loss will be the overdrive enable - and that's actually not through the PCM, so keep that wiring and you should be good!
You may have problems with the TV cable attachment, but folks like Lokar make kits that can be fitted.
You may want to make it easier, and find a 727 to put back there instead. You'll lose overdrive, but depending on the carburator, you may be able to use off the shelf TV hardware (well, it'll be a "kickdown lever" instead.)
If you have cruise control, that may be hurt worse since the 1994 used the ECU to drive the cruise servo. You can hunt up a mid-to-late 80's cruise control setup (it spliced into the speedo cable) if you want cruise. If you don't, then ignore this *grins*
Speedo is electronic, but I THINK it's driven right off the VSS, so that won't matter.
Your biggest problem will be that the factory tach is driven off the ECU, not off the motor, and is 2 pulses per revolution. This isn't actually that hard to fix on a V8, with 4 pulses per revolution - a simple /2 gate setup will take care of that. It will still need the input cleaned up (so you don't get, say, 20 pulses per spark due to the ringing off the coil).
That covers most of it, I think.
Oh - while doing this work, if you don't grab some headers, at least find some 92-93 exhaust manifolds. They're bigger, and flow a bit better, than the 94+ manifolds do.
RwP
