TR3 cylinder head: high or low port?

[anders@ull.biomeklab.aau.dk (Anders Odgaard)]

I'm currently rebuilding the engine in my TR3, and I have a few questions 
relating to this. Hope that these have not recently been discussed at length.

1. How will I know which cylinder head is in my car (high port or low port)?
2. What are the advantages of a high port head compared to the low port head?
3. Does it make any sense to install Webers on the low port head?
4. Have anyone experience with modifying the head for lead-free gas?

Thanks,

Anders Odgaard
Aarhus, Denmark
1956 TR3 TS11429LO
1983 Rover 3500SE