I had the stiff cable symptom on my 83 and the local Volvo repair place said "worn-out clutch". He also noted that the cable adjuster was at the end of its range. I had to believe him since the cable was new only 30,000mi ago. I went for the OE (Sachs) kit, a few extra bucks but cheap insurance - it's not a job you'll want to do twice. As Richard (Hillsboro) said, get the flywheel resurfaced to mate perfectly with the new clutch. The Sachs kit comes with pressure plate, disc, release bearing, and alignment tool.

I now have (a) thinner wallet, (b) nice light, smooth clutch. The mechanic replaced the rear crankshaft oil seal ($15) while he was in there, as it usually needs it and 99% of the labour is already done with trans, clutch, and flywheel off. A leak there will ruin your new clutch fast.

I asked for and got the alignment tool (he had plenty), as I may one day be brave enough to try replacing the flywheel ring gear on our other 240.