Dear Roman.
There is no special spare parts lists for 550x an Tornados. Both engines were almost standart, just the pistons diameter was oversize, they may use an special fuel pump Johnson type,
and some had an special modification in the carburetors cups in order to keep fuel inside
in the sharp turns, rather easy to do. Manual start to save weight.
The extra power comes from the oversize pistons, mainly.
They were all short shaft.
Later came the model 600SX with different gear and propeller, they keep on using old Johnson model jet exhaust, and this model has an special spare parts list, of which I have a very bad photocopy, made in the late 70´s. It was given to me from a friend in Norway.
The power output of the 550x and Tornados over the standart production engines, was very big, so the standart engines could not compete at all.
I am quite sure about that info just because my father was an Archimedes Penta dealer,
and I was very interested in any new modification I could do to my racing engine, and I had then direct link with the Importer for Spain.
Best regards from Palma de Mallorca, Balearic Islands, Spain

ich