Ok....
So I have the MSD distributors, boxes, brackets, coils, etc. I want to pull out all the old TB IV stuff, module, and all that. I have done this in a car before, but am now a little intimidated to do this on my own in my boat. It doesnt look that bad but am confused on all the wiring back there. How do I know what needs to stay, and what can go? I have the merc manual that shows the wiring diagram. Just looking for some clarity and what all gets ripped out, and what has to stay, what do I need to be careful of, etc. Any info on this to make it an easy swap out would be MUCH appreciated!

This is in a Cig TG. Motors are stock 525sc's for the most part... Long blocks have been upgraded to new 502's but I dont think that matters. The entire ignition system is stock as it came in that boat with 525sc's
Thanks!

I just did this and cleaned the harness up on mine. Removed the stock ignition module and knock sensor and replaced with MSD dist., coil, and 6m2-L box. I simply followed the Merc manual that had those wires and either cut them completely out or cut them then shrink wrapped them up and taped back into the harness. I even used one of the hot (keyed) wires for connection on the MSD box.... cleaned them up real nice.

Thanks ng.... anyone else ?? I am really looking for some feedback on how to do this..... thanks.

A little off subject-- P.M. me if you want to get rid of the modules (if they are V8-24)