do you have the cam lock tool?
and the pump lock tool?
you need to lock the pump pully first then remove the pump belt and pully from the head/camshaft.
put the engine on tdc and install the cam lock tool in the back of the cam where the pump timing belt use to be. set the flywheel on tdc. loosen the timing belt pully bolt and tap the pully with a rubber mallet, so it moves freely on the camshaft (just a press fit), remove the bolt compleatly and put blue locktight on the threads, install the bolt snug, install the belt , make sure the crank is still on tdc, snug up the cam pully, move the waterpump to tighten the belt, tighten the cam sprocket to i think 20 ft/lbs, remove the cam lock, use a pipe wrench or vicegrip to hold the cam steady between the cam lobes, tighten the cam bolt to 68ft/lbs, put the engine back on tdc, install pump belt, turn engie over by hand.
note. without the cam lock you probably never get the cam to crank timing correct and you will have valves hit pistons.
best of luck
chris