Well 3 speed trans are about obsolete now almost everything has went to 4 and 5 spd transaxles trans.
Clutches have remained the same for a long time.
A dry clutch disk plate with a pressure plate to compress and hold the clutch plate to the flywheel.
And a throwout bearing and a manual fork or a hyduralic slay cylinder to push the throwout bearing against the pressure plate to release the clutch plate.
But way back in the old days they had some wet clutches that ran in oil. They were called fluid drives almost like a automatic trans.
You might get some repair manuals and learn some more about clutches.
Also some repair books on real old cars would be interesting. And yes they had automatic trans way back then to.
MT