Here is an Ebay auction for an NOS C2AZ 7534 A clutch pedal assist return spring by Ebay member "shanty137" with a starting bid of $48.00 and a Buy-It-Now of $69.00:
You are bidding on 1 NOS Ford Clutch Pedal return assist spring. The number on the sticker is C2AZ-7534-A , From the research I have done, this should be correct for 1965 - 1968 Mustangs with a manual transmission, maybe some earlier applications as well sinse it has a 1962 part number? . Please confirm this is correct for your application prior to bidding, I do not acccept returns.