The Tbird Supercoupe T5 had a hydraulic clutch. You may be able to use it's hydraulic throwout bearing, but I'm not sure about the bellhousing.
It is a nice piece made by AP (they make formula 1 brakes and other nice stuff) and I think it would be much better than the slave cylinder pushes the clutch fork method.
There are lots of kits and DIY plans for hydraulics in early mustangs because cables don't adapt well and the Z linkage is a joke after the motor mounts get a little soft.
Actually im sure there are plenty of kits for a kit car. Pretty much every one ive worked on has a hydraulic clutch (including factory five ones) I know ive seen CNC ones on them before. Id check around on kit car sites.
Not sure if you know this one www.FFCobra.com hope this helps
Plagerized this from another site....
I got my Hydraulic throwout bearing from
Mcleod Industries. They are located in Placentia , Ca.
You have to call their Tech line at 714-630-3668. Tell him exactly what you are doing and he will tell you what part number you need and what spacer you need if nescassary. It is a Pain in the but because you can only call him between 10 and 1 or something like that. Anyway, once you have the part number call their office at714-630-2764 with the part number and order it. Expect it to be about 300 bucks. If you dont want to go that expensive, Kaufmann Products has a slave cylinder adapter kit for about $180. I recomend just getting the hydro bearing instead though, it is so much easier and cleaner looking.
I have one ot he McLeod hydr. T/Os on the toploader of the 67. Love it. It was about 300 for the kit (bearing and M/C). I think I remember seeing one for the Tremec as well. You will also need to purchase a hose to connect the M/C to the bearing, not in kit (at least not in mine). Instructions were pretty straight forward. Not hard to install system.