What are the torque specs for a flywheel and pressure plate on a Datsun 240Z

Yes. There are flexplate flywheel torque converter bolt kits available online.

flywheel is connected to the crank shaft it stores the energy when in excess and deliver when engine req it

The flywheel in an engine stores the energy given to it by the moving pistons and smooths the rotation. In single cylinder engines the power stroke of the piston would cease immediately if it were not for the flywheel continuing the exhaust stroke to rid the cylinder of the spent gases.

Yes, it has one.