the part of the cap where the old internal coil was ? rigth now you are using a external new coil? if this sounds right to you ? you need a adapter for this put a post where the old coil was so you can pick up voltage and send it to the plug wires. on the cap look for a good thick cap with brass terminals and rotor. you need a coil internal in the cap or external out side. the msd controls duration and how many times multiple spark but you still need some type of coil