69 Cuda factory tachometer wiring (photo of rear connections)

Hmm found this photo and commentary in another thread.
Looks like I've wired mine correctly, I suspect i need to take things apart again and check the needle.
sigh

"The Spade terminal on the back of the tach goes to the negative side of the coil (signal) gray wire.

The longer stud goes to 12v switched power. (blue harness,goes to fuse block for acc.)

The case is ground."

Factory Tach Wiring

tachometer 2.PNG