Tim;

I agree with all of Rhys' comments..the friction at the extremities of piston travel can be significant in a newly honed bore with virginal rings (particularly the Deves brand)...and moreso after the first few turns when much of the assembly oil is wiped away and things are a bit dry...but I always give a newly rebuilt block its first twenty or so turns by way of the crankbolt...without the rockers installed, so no camlobe to lifter friction either...and I swear I can feel the force required to turn be less by the twentieth turn (this is by feel and a WAG...I haven't measured this)...as long as you can turn the crank and there are no abrupt stoppage points suggesting an interference, keep trying and report back if you notice it getting easier to turn after twenty or so...only after that would I even think about installing the valvetrain, and adding its friction...besides, a 20" breakerbar applies double the torque of a ten inch adjustable/crescent wrench...could it be as simple as that?

Cheers