1) Remove the pedal board. (Unless you have hands like a 7 year old school girl) There is an inspection plate where the pedal board screws into at the top of the center tunnel, remove that too.
2) The throttle cable is attached to the pedal by a ball joint that can be removed. Snap the joint off the gas pedal, ( I used an open ended wrench to punch mine off) and then unscrew the brass cup from the cable.
3) From the engine bay, unhook the throttle cable from the motor and push it down below the engine so that it is hanging under the car. I have a conversion, so I just removed mine from the linkage attached to the Tranny.
4) Have your car "assume the position" (jackstands)
5) From under the car, pull out the old cable from the fire wall.
6) From under the car push in the new cable. (you do not need a leader line, the cable will find it's way up the tunnel just fine)
7) Go forward and dig around the front of the tunnel near the pedals with your fingers until you find the end of the throttle cable. You may need a mirror to find it, but I had no problem finding mine. Screw on the brass cup to the end. Make sure the cable did not wrap itself around the clutch cable. (You'll know soon enough if it did or not once you get the car started)
8) Snap the ball cup back onto the gas pedal. Do not yet replace the pedal board, carpet or inspection plate. Lower the car back to the ground and attach the engine side back together.
9) Sit in the car, and work both the gas and throttle cables. Do you feel ANY dragging, or hear what may be a wrap or three? The gas pedal should go down smooth and come back up smooth. Any hesitation means you have a wrap.
I had to install my cable 3 or 4 times either because either I'm an idiot, or just have really bad luck, or maybe a combination of both.
Flashlights are your friend