I have a 1996 Manta Ray with the Merc 5.7 set up. I need to know how to set the timing. I have the distributor with the module mouted on it. I beleve that it the thunderbolt IV. I was told I needed to ground out the distributor to set base timing(purple/white wire) I do not have a knock sensor. I just need some advice on how to time this correctly.

