Reading the manual for the Terminator X Max and it says "Tach Output wire provides a 12V square wave output and can be used to trigger a conventional tach"
Which wire in the engine bay can I tie this wire to for the tach to work? If anyone has a link to the wiring schematic that would be awesome.
Appreciate the help. THANKS!

 

Your stock tach wire is connected to the coil - terminal, same place as the distributor.

 

Thanks Oldcutlass. I figured this was the case but wanted to confirm. So to clarify he Holley wire is an actual 12v signal and not a ground type activation? Being that the negative pole on the coil is the source is a little confusing. I can go ahead and wire the the Holley output to that 1 if 2 wires that was at the negative terminal? The other went to the bottom of the distributor.
THANKS AGAIN!

 

I don't know anything about the Holley system, but the factory tach is designed to connect to the NEGATIVE side of the coil. With the conventional points-style ignition system that terminal oscillates between 12V and ground, depending on whether or not the points are open or closed. GM's factory HEI has a TACH terminal that replicates that signal for tachometer use. If this is also what the Holley system does, then you are fine.

 

The factory tach in my 69 worked fine with the points ignition (obviously) the HEI, then the MSD6AL ignition box, and finally the Holley Sniper. I’m guessing you will be fine.

 

Thanks guys!

 

Just ran across the X max swap. .I'm headed that way also with a G block 400 and a late build 4L80e( Trans lines up front) 342 in the rear .What is your combo ? Any intel you can share.