from my old memory, the ball shifters were round, while the t-handle shifters were either a rectangular stalk, or a round one that was a smaller diameter than the ball knob shifter. years ago, i machined a small, round, push button shifter knob to replace the cracked t-handle on my brother's sattelite/roadrunner from 1" [or so] round aluminum stock. worked as good, or better, than the t-handle, and looked good as well. it was a simple, two piece deal with a spring and retaining set screw. super easy to make. when the car was scrapped, i kept the knob. it resides in the "mess" somewhere.......