According to the very helpful person at the Tohatsu-Nissan technical help desk [972 323 6003], the torque should be 24-26 nt-mtrs. 26 nt-mtrs coverts to 19 ft-lbs.
Who to believe, according to Service Manual M10 bolts specs are : 23-31 NM or 17-22 Ft/Lb. Usually adjust 30 NM with 3 torque steps of 10 NM each till 30 NM is reached. Anyway whichever torque setting is used adjusting head bolts, must be retorqued after 20 worked hours for head gasket to seat & seal properly.
There is a torque sequence, you start from the center of the head on bolt #1 then #2 etc.
Like Sea Rider above, start at 10 NM,then 20 NM, then 30 NM
You need a factory service manual
