Foghorn -
The MSD box needs good strong battery power to produce the spark it does.
So if you can, it is a good idea to hook the
heavy gauge red power wire directly to the battery positive starter solenoid lug.
If I am feeling extra cautious, I will put in a 50A maxi fuse between that connection and the solenoid lug and solder the terminals before attaching them to the blocks/terminals.
The
smaller red wire lead can be attached to the I' terminal of the starter solenoid as it is only a switched 12V for triggering the box ( read 'no-amperage )
This may be a pink-wire depending on config, and is fused from the harness.
Depending on what KMP you have you could be able to tone out ( trace ) the tach wire.
it is yellow as it leaves the K' gauges,
http://www.thomaskirkham.com/4inchinstructions_2_.pdf
-- but it may change color along the way to a purple wire ( if it is the KWIK-WIRE harness. --
http://www.kwikwire.com/DocDownloads...ion%20Book.pdf
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if that it the case, that purple wire should attach to the white or gray lead -- or even plug into the side of your MSD box ( refer to instructions )
As for the ground wire I like to make sure it is connected to the same ground log that is also attached to the engine ground lug.
without knowing for sure ,IE; seeing the con-fig --this is the best ideas i can offer.
Steve