so for the last 3 days i have been working on building my head. i have a gsr head and i bought stage 2 cams, valves, springs, retainers. i took the whole thing apart spent half a day cleaning the head i took out all the valves and springs one side at a time. i bought grinding compound and seated all the valves put on new seals and put the head back together. after putting in the new head gasket i set the head back on the block and fastened it to spec i set the cams by the book used lube torque wrench and gasket sealer in the needed spots. i changed the oil new anti freeze hooked all hoses vacuum lines and sensors back up. i set the timing at TDC with the gears and marks on the crank. i turned the crank at least 6 times by hand. put the wires in the proper order. i turn the key and the car cranks over but doesnt start and theres also a knocking noise coming from the motor what could i have done wrong? any help would be much appreciated

thanks,
dom