No, A-body disc master cylinders were either 15/16" bore or 1-1/32" bore. B-bodies came with 1" bore (also 1-1/32 and 1-1/8), and all these master cylinders are interchangeable, so you could wind up with any of those sizes if you wanted. Note that the pushrods will be different for power and manual, and some may not have the correct piston stop for manual applications.
