That sucks. I know because I've attempted to fixed many things, only to make it worse. Still, the experience counts down the road.

I did some searching, but couldn't determine whether tachs are interchangeable. It seems to me that they should be, but then again I wouldn't be surprised if there are signalling differences between different-cylindered engines. Were the donors cars both 8-bangers?

Also, the evolution of the ignition systems over time suggests to me that the window of interchangeability will be limited to those models sharing the same components. To clarify, our 1986 tachometers get their signal from the EZL ignition control unit. Do you know if the donor vehicles were so equipped?



I'm sorry that I can only offer more questions. I hope that a guru will respond soon.