The original Lancia Stratos wooden gear knob does not really fit on the 6-speed Alfa Romeo gear lever as the Alfa Romeo shift stick has a lockout mechanism (for reverse gear). So it’s pretty hard to find an item with the correct structural layout and furthermore looks similar to the original Stratos shift knob.
Due to these reasons the consequence was the creation of an own design. Lister Bell provided measurements that were considered for the shift knobs’ styling.
Design-wise the new gear knob should reflect the shape of the original combined with purism as it can be seen on gear knobs of older Ferraris and other 70s sports cars.
Design sketches, 3D data and technical drawings were created and then sent to a factory specialized in the production of metal & aluminium parts. A few weeks later the shift knob was ready. It came out exactly as instructed: New Design/Shape – finished off in black anodized aluminium with a slightly engraved shift pattern.
Michael Leonhard's Blog 