810 Dunstall cylinder with a 850 head

Hi All.
Can i use a 850 head with a Dunstall 810 cylinder?.
Thank you
Piero

I tried it on my spare parts and seems the head bolt spacing is OK but the Dunstall 810 cylinder bore is 76mm and the 850 head chamber is almost 78mm.
Also the Dunstall cylinder uses some odd bolt thread sizes.

Dunstall 810 kits were for 750 engines, so the head bolt pattern is for a 750 head. 850 head will not fit.

Ken