I was wandering what the difference is between the 70-71 clutch pedal and linkage and the 72-81 also will a pontiac z bar interchange with a small block chevy. Thanks Dave

Not sure, but I think the later clutch pedals were smaller, so the rubber pad will be smaller too. I doubt there is any other difference.

Some 1970 parts are one year only, I have not ever noticed anything with the clutch pedals. I have noticed the brake pushrod hole in different locations year to year on 2nd gens