This thread definitely caught my eye, as I've had a couple 1965-66 models with the z-bar..including my current '65. One HUGE problem I had once with a '66 was when a chunk of the cast iron around the linkage pivot stud on the 289 block broke off, taking half the threads with it. Don't know if anyone else has had this happen...but to fix it, you have to pull the engine and have the bolt hole rewelded/retapped. A huge PITA...!!!

Only problem I've encountered with the z-bar setup, other than that, was the clutch rod slipping out of the clutch fork once due to incorrect adjustment. Otherwise...system seems to work fine and you do have good feel for when the clutch engages.