With my original 73 144 35 years ago, I drilled a hole in the firewall and in the clutch pedal, hooked up a 240 master cylinder to the 140 OE clutch pedal, and.... that's as far as I got before I went crazy in 1991 and got foolishly and painfully involved with other gadgets.
I never sorted out the 144 slave cylinder or hoses. There's never been any off-the-shelf kit AFAIK for a converting the mongrel clutch cable to hydraulic, and in those days, nobody told anyone anything about mods to Volvos. No TB or Oz Volvo in those days, so you were on your own.
(The mongrel clutch cable broke twice on me without warning, so i was very keen to get rid of it).
With the benefit of hindsight, the challenge is to get a suitable master / slave cylinder combination, and then attach a suitable custom-made bracket to the bellhousing for the slave cylinder. I got the 240 master cylinder to attach to the cable clutch pedal and physically fit on the firewall, and had plenty of clearance to the rear Weber DCOE.