Bitz EFI, MSD 6A Wiring Question
 

I have been searching forums and I'm stuck on how to wire up my tach. I'm looking to see if anyone has ideas or has encountered this problem. Perhaps I'm mis interpreting the instructions.
I have a 82 SC, my engine is rebuilt, and I am installing the Bitz EFI kit with a MSD 6A 6201 ignition controller.
Before I got into wiring for the Bitz kit, this car had a permatune CDI box that and some of the wiring for this was hacked up. The harness connector was hard wired. I think I figured out all of the wiring except how to hook up the tach.
Maybe I'm interpreting the instructions incorrectly, but it seems that the MSD and Bitz tach wiring instructions are conflicting.
In the Bitz instructions, the Megasquirt Blue wire needs to connect to the Tach output, which is the black & purple line from the tach.
The MSD box has a Grey Tach output wire. Is that supposed to hook up to the Tach black and purple output?
I'm stuck.

I have an MSD box and the Bitz kit on my ‘77 and just went and took a look at how mine is hooked up and I have both the grey from the MSD and the blue from the Bitz hooked to the purple/black.

My car tach and the computer tach display work properly.

Wow- thanks for checking for me. that was my conclusion as well but I was not sure. Perhaps I was over-thinking the problem. I'm an old time electrical engineer, and I was looking at the MSD Grey wire, and the EFI Blue wire as tach signal analog outputs, and the purple &black wire as tach input. You really cannot join 2 analog output signals, it did not make sense to me. I would have to assume tht the analog output connections are sophisticated enough to deal with this scenario.
I'll connect the 3wires as you did. Thank you.

I think that the Bitz kit isn’t using the blue as an output, but gathering data as an input, so your engineering is still probably correct.