Here's yet another tach question.

My 1998 Durango (originally a 5.9 V8 with 46RE) is getting a 2004 LM4 5.3L Chevy V8 and 4L80. I've been doing some reading on the affected crank sensors in order to get a tach reading and will list what I have come up with so far (this is all prelim work since the truck is weeks away from running):
The Dodge tach is connected to the PCM via serial (CCD bus) data.

The Dodge PCM gets a crank signal of 8 pulses per revolution (PPR) from the 3-wire Dodge crank sensor. It uses +5V from the PCM, then outputs a signal and has a ground as well. The PCM takes this 8 PPR and converts it to serial data for the tach.

The GM sensor outputs a crank signal of 24 PPR and also uses 3 wires. They function the same except the GM sensor runs on 12V while the Dodge runs on 5V.
Possible solution:
HP Tuners has a user-configurable tach output for the Gen 3. I can vary the number of tach pulses output, and in theory make them 8 vs the 4 used in the Gen 3. Could the PCM tach wire be connected to the Dodge PCM crank signal input so long as the Dodge crank sensor ground is also tied in?

It may boil down to if the HPT tach output circuit shares the same ground as the crank sensor. I don't know enough about electronics to know if removing the Dodge 5V from the circuit makes it unusable.

I'll attach a sketch I made showing the two OEM setups and a proposed solution. Any thoughts or advice are welcome.

HP Tuners tach output to Dodge PCM.jpg