Set the crank on tdc for #1 cylinder. To be sure you are on #1, remove the spark plug and hold your finger over the hole and turn the crank to the tdc mark. As you do, your will feel hard pressure on the plug, indicating that #1 is on the compression stroke. Remove the dizzy. Rotate the shagt until the drilled mark on the shaft alighs with the cast mark on the housing. Slide the dizzy into the nole while you hold the marks in alignment, centering the adjustment slot on the stud. Let the shaft turn only when the gears start to engage. The rotor will align to about 9 oclock. this will set gross timing. Fine setting is done with a timing light, vac line to dizzy removed and pluged at 750rpm idle, 7-10*btdc, i.e, left of the zero mark.