Heres some pics of my throttle cable mod. The mods I did was add a throttle return spring, moved the cable in on the bracket so it pulled the throttle straight down vs at an angle how it is stock. With this kit its also adjustable so if for whatever reason theres slack on the line you can tighten it up so it will pull when the pedal is higher. The kit cost 24.99 and only took about 10-15 minutes to put together from scratch.
http://www.autozone.com/R,NONAPP4194/store,2591/shopping/accessoryProductDetail.htm
What I did here was take the cable out of the tube. One end of the cable has a stop crimped on from the start. That is the end you want on the pedal. Slide the stock spring over throw peice onto the stop. Next put the spring on the outside of the pedal and and put the cable through the nut, then route the cable through the firewall into the engine compartment.
As you can see in those 2 pictures you slide the spring through the tube and put the threaded end through the firewall with a washer on each side. Tighten the nut on the inside of the truck to the tube to secure it to the firewall. Next what I did was remove the stock bracket for the throttle off the manifold and lengthened the slits to allow the linkage to have a straight pull at the throttle. I took the peice that clips on throug the the slit and snapped that into place while cutting the access tubing away.
You then have to drill out the throttle arm provided in this kit to slip over the arm on the manifold. Once thats done go ahead and slide it on and use some sort of set screw peice to prevent it from sliding off. Unthread it about half way down so that way if you ever needed to take slack out of the cable you can just easily tighten that once peice to tighten up the cable in seconds. Once complete pull the cable taught so the pedal is all the way up and cut the cable to the top of the throttle arm from the kit. I cut mine about 1/4 inch below the top so I would have some room to adjust as needed.
At this point its just setting it up to how you want it. I added another throttle return spring to my setup just for peice of mind incase something was to fail.