The speedo there are two main types on the 340 and 360. Smiths clocks have square light on the fuel and temp warnings, the later VDO lights are round. There a few types of speedo for the early 343's and would be best to include a photo of the type you need. The cable needs to match the speedo as the fittings are not the same.
Door handles is it front or rear ones you need or both?
Not sure about belt.