No sir. The pilot bushing is the same. The difference is the crankshaft register where the flywheel/flexplate mounts. I believe the split is 68 and up is the larger crank register and 67 and prior is the smaller. So you have to use the matching flywheel/flexplate/torque converter for the given crankshaft register size.
Thank you for clarifying that. I have the right bell, the trans, and all the right clutch stuff, so looks like I’ll just need a Z-bar (and the 300 other things I don’t know I need yet).