The original clutch clevis on a 914 was plastic and looked like this...
Click to view attachmentIt was superseded by the metal one we are all familiar with.......
Click to view attachment You will notice that the "ears" on the trunion don't really fit the clutch fork. When Porsche superseded the trunion, they didn't update the length of the clutch cable. So you have to put in a spacer to get the full adjustment on the cable.
If you buy one of these from Weltmeister, it works much better.
Click to view attachment It is for a 911, so you have to trim off about 1/2 inch from the end. Once you do that, it fits right.
And you don't need a spacer. I put one on the original six, and it works great.
Clay