[fred cook]

I have a newer but similar system on my engine. The system I have is made by Electromotive and is the XDi system. It looks like what you have is called a "wasted spark" system. It works as follows: When the #1 piston is at TDC and ready for spark, the #1a coil fires both the #1 and #4 plugs. The #4 piston will be at BDC on the exhaust stroke so there is nothing to fire in #4, thus the "wasted" name. If 1a if firing the upper plugs, the 2a coil does the same thing for the lower plugs. Thus the 1/4, 2/5 3/6 labeling.

As for timing, I use 8 degrees of initial advance with 20 degrees coming in at around 3000 rpms. Adjustment is made via knobs or screws on the timing control box. The system should require about 1 amp per 1000 rpms so if you used a redline of 7000 rpms, it would require about 14 amps (1 amp per 1000 rpms per coil unit). The system should be wired using relays wired to cut the circuit when the ignition is turned off. Otherwise, it would run forever! As for parts, your older system is so much like the XDi unit, parts like the crank signal wire, etc might interchange. Good luck!

The coils should be labeled (starting at crank pulley end of the engine:

flywheel end
3/6
2/5
1/4
crank pulley end

#1 piston is the left rear most cylinder.