you need the piston in cyl #1 to be at top dead centre and both intake and exhaust valves shut, mark on the dizzy case where the contactor on the cap lines up, turn the dizzy in the hole until the rotor points to this mark, this means that the ignition circuit is complete and cyl 1 will fire when the piston is at TDC. if nothing happens when you try to fire it up then your 180' out, simply rotate the cap 180' or remove the dizzy and put it back in so that the rotor points 180' from your original mark on the housing, then put the cap bac on. the large caps only go on one way. be careful abou relying solely on harmonic balancer timig marks, they can slip and give false timing readings. u should check TDC with a screwdriver in cyl #1 being careful not to poke it into the bore...