cable clutch assem. vs hydraulic clutch assem

I recently did a 4spd conversion on my 65 barracuda and am having problems building enough pressure with the hydraulic wilwood master cyl. to fully ingage my clutch to shift, plus it is starting to seep fluid out the back. Wilwood says it should handle the 2800lb clutch i put in and should not leak. I still have to talk to the place I got the cyl. about replacing it. Has anyone here ever done a cable set up like in a mustang? They look pretty simple?