z bar modifcation?

ok so I wasnt even calling it the right thing its the clutch TORQUE SHAFT and what I am in process of doing is converting a 65 barracuda to the larger 10.5 inch bellhousing and clutch, what I am looking for is the amount I would need to cut out of the original TORQUE SHAFT in order to make it fit, or is it more of a measure it and then cut depending on application type of situation? sorry I am new to the 4 spds and I am still learning

any help would be appreciated