MSD Optispark Help..

I have a 97WS6 with a 95 motor installed. I purchased a used full billet MSD Optispark that was pulled from a 96Z...My question is there a difference between the optisparks from 95/96? I didn't think there was..but the MSD is not plugging into wiring harness..and the dowel pin is not fitting into the cam slot? Just need some guidance and thanks all...









