Will a 2.7 Tach work Properly with a 3.2 Engine?
 

As the title describes. Will a 2.7 Tach work properly with a 3.2 engine. I am starting to wonder if the 2.7 tach I am currenly using shows a higher idle speed then the engine is actually at.

Does the DME take any info from the tach or does it just send the signal that lights up the upshift arrow?

There is no upshift arrow in a 77 tach
Yes, I have installed several early car with 3.2 and always used the tach in the car.
The DME sends out all info, takes nothing from the tach, just from the engine sensors
the tach is driven from a connector of 3 or 4 wires in the main wiring harness. Tach wire is Black/purple. Another wire in the connector runs the relay for the fuel pump.\

Bruce