MSD ignition wiring

I recently received a MSD 6A box (for free!) from my dad. I'm trying to figure out the wiring, and I keep coming up with extra wires, so I don't know if those just aren't needed or if I'm missing something.

I'm installing this on a 1980 Spirit with a 258, I have a Duraspark module and a TFI cap and coil. The duraspark has 6 wires involved- 3 connected to the distributor, 1 runs to the coil, one to the solenoid, and one to the harness on the firewall (can't find the interior wiring diagram right now, but I would guess that's power from the ignition switch?).

Here's a link to MSD's installation instructions, pgs 17 and 18 are where the diagrams I'm looking at are. http://www.msdignition.com/uploadedFiles/MSDIgnitioncom/Products/Ignitions/6420_instructions.pdf

MSD provides a lot of diagrams on installing the box, and there are 3 I see as pertinent. There are two methods for using a duraspark system, and one for a TFI.

So there's my first question- since the MSD box is taking the place of the ignition module, can I just remove the duraspark module and wire it up like it's a TFI system? This would mean, as best as I can tell, none of the wires coming from the distributor would be connected to anything, one wire to the coil would have nothing connected to it (and no signal from the dizzy). So clearly there would be a little more involved, because that wouldn't work.

Next up are the Duraspark methods. One method doesn't involve the dizzy, and I'm having trouble seeing how that works, too. The other has you splice into the 3 wires coming off the distributor to trigger the box. That makes sense, now I have a signal to the MSD box, and then a signal to the coil. And I have a connection to the coil coming from the MSD box. So that's good. But here's the problems I see- the wire from the duraspark module to the firewall is now left unconnected. Maybe I don't need this since the box connects straight to the battery for power? And the wire from the duraspark box to the solenoid is also left unconnected. Can this just be left out? Last problem- when I connect to the coil with the MSD box, I leave one of the coil wires disconnected (see the diagram on the top of page 18, that's the one I'm working with here). Makes sense. But I'm connecting to a TFI coil, and I'm not positive which to leave disconnected. I know the white wire is the one that doesn't get used (per MSD instructions), so I would guess that's the one I leave disconnected, but I'm not positive, and I really don't want to just guess and end up burning something up.

I know that's hard to digest, I'm having a hard time putting my thoughts into writing that makes any sense. Anybody have any help they can offer? Or have any questions about stuff I need to clarify?

Maybe I just need to call MSD, too.

Thanks for reading, and for any help you can offer!

http://www.skidmore.edu/~pdwyer/amc/eagle/gif/ssi_80.gif

This is the wiring diagram or schematic of the ignition used on your car. Are these the parts you are referring to?
Of so I do not see how they relate to the pages you are referencing? There are three wires coming from the distributor that would be used as the pick up for the signal to be generated for the spark. The Dark Green wire would be the switched voltage from the ignition switch and a yellow wire which comes from the fuse block to supply 12 volts DC on all the time.
This (from a quick look anyway) seems to indicate that this diagram:
Installing to Points/Amplifier Style Ignition.
and the chart located just above this have the information needed Or the diagram on figure 11 or page 11.
All of the rest of the diagrams seem to indicate using an MSD distributor.




Edited by uncljohn - Apr/20/2015 at 2:30am

You can buy a plug adapter for the distributor/ msd box. Part# 8869. it plugs between the box and dizzy. It makes it a lot easier to figure out the rest. Summit racing sells them

Wire direct to dist using mag trigger, just remember wires at dist are opposite if msd colors