1978 Land Rover 3 Series - Santana, engine 10J, diesel. Engine head features i

I recently acquired a 1978 Land Rover 3 Series - Santana, engine 10J, diesel in Brazil. I'm restoring the engine head (engine is smoking and has no power). I can't find the features of the cilinder head. I need to know if the height of the head is original or if it has been reduced in any previous repairs. Does anyone know the height of the original head(if possible in milimiters)? Thanks in advance
Afonso