How to plug Mallory Tach adapter?

[Lazeum]

There are many questions and threads about tach adapter but none of the threads shows how to tap the adapter. Of course the tach doesn't work (I wouldn't ask the question otherwise )

My setup first: 72 240z with L28, Mallory Unilite ignition, Mallory Hyfire VI-Al.

 

I found the manual not clear, I'm confused and I would like to check is everything is understood before doing mistakes with the car

There's also a diode provided with the adapter, do I need to install it? I haven't read anything about it.

 

I've made a pic with how I think I should tap everything from the Hyfire unit manual as well as from the adapter one. Am I correct

Please advice

 

 

Can't we also plug the tach as it was before the ignition, with a wire going from the (-) side of the coil to the tach? Will I fry the tach by doing it???

 

Thanks guys in advance

[Lazeum]

On Classic Z board I've found some info about the MSD tach adapter which seems to be very similar to the mallory unit. I guess I was right about how to plug it

http://www.classiczcars.com/forums/showthread.php?t=13085

 

another question:

I cannot find the tach wire According to service manual, it should be a black/white wire. I highly doubt the previous owner who installed the system cut or removed the wire. I've check everything with no luck, I did not find the tach wire .

 

The obvious solution (but not the easiest) would be to check the wire right behind the tach, cut it (since I don't know where it goes) and replace it with a new one.

 

According to what I've seen my tach is the 4 wires version, where should i then plug the 4th wire since the mallory Hyfire unit has only one wire for the tach?

 

I put picture of the system, please I need help

This is on the left fender (You can see the carb on the lower left corner)

 

 

Pic of the bottom of the tach. I do not see neither the white/black wire the service manual is talking about...