SpectorV wrote this below, which has info on how to adjust your clutch cable if you have the factory setup...
Shared post from 'Mustang Evolution' by SpectorV from thread 'Clutch adjuster info...':
if your cable is 100% stock and never replaced you should notice a little difference in going with a new cable (you can just buy an OEM ford one).
You should notice your clutch petal has a flop in it (not firm and you can lift up under the bottom of it). In order to adjust it the way I said it needs to be you have to take all the slack out of it due to the cable being how long it is.
You can have the stock quadrant do this for you and it MAY hold. Mine has for 3 years, if you shift very hard or touch the underside of the clutch petal and raise it up it will unadjust.
Crawl under the drivers side dash upside down and push the clutch petal i with one hand and hold the quadrant with the other hand. Ease out on the clutch petal while keeping pressure on the clutch petal as the clutch nears its all the way out level you will hear a noticeable click. Thats it taking up slack, do like 2 clicks and see how it feels. Test to make sure you didnt take up to much slick as I mentioned above.
this is kind also how you readjust the quadrant if you replace the clutch cable (which is quite easy)