Thanks, Angel...
The seller of the first head (the one from the site subito.it, the italian equivalent of LBC) said it was an 850 one because he found it in a garage near a 850 r5, but now, as I wrote I was not interested 'cause I was looking for a 1108 one, said he was not sure, it could be another kind, let see a mechanic... So not reliable at all, on my own.
Piston and liner are inside the head? I am very ignorant, and I am searching to learn... maybe I need some specific lecture... If I am right, if I buy a 1108 head, I have only to swap it with my actual 956 head and go... But maybe gear ratios are too short with my actual gear?
Those heads I found are quite cheap, but if there is so much work and pieces to look for, maybe finding an entire gtl engine and gear could be, at the end, cheaper...