The steering box itself is the same but the shaft and the sleeve/tube are substantially different. In the pictures below you will see the steering wheel end of
However, the length may differ between cars. Not only are the overall lengths different but the steering lock block too. In fact the Spider and GTV are the same but they differ from the Berlina. Here are the steering shafts:
•Berlina •GTV •Spider
Similarly, the sleeves/tubes are also different.
I get 620mm from the bottom of the mounting plate with 4 bolts to the top of the sleeve from a Spider/GTV.The long sleeve is 640mm or 20mm longer. When ordering a re-conditioned box complete unit, it is important to determine which type you need.
The worm gear end of the steering shaft is the same for all three - internally and externally, the Burman boxes are identical and interchangeable. But, the LHD is not interchangable with the RHD and vice versa. The threading is different.The short column should be 834mm.
This is the crucial measure of the sleeve below. It is either 620mm or 640mm.
Two good Pitman pullers that might help to pull. Your local machine shop should have them or similar ones.
Yet another picture of what's inside the Burman box.